Last reviewed on 2026-09-25 by the Tartare.org editors.

Tuna Avocado Tartare Bites

⏱ Prep: 45 min 🍽 Makes: 24 pieces 📊 Difficulty: Easy
Tuna and avocado tartare canapés on cucumber rounds

These are one-bite canapés of tuna and avocado tartare: a heaped teaspoon of soy-sesame tuna, a little avocado, and something crisp underneath — a cool cucumber round, a baked wonton cup or a thin crostini. They look like caterer's work, but everything except the final assembly can be done before guests arrive, and the recipe scales cleanly from 24 pieces to 48 or more.

Built on the original. The topping is our original Tuna & Avocado Tartare, cut a little finer and dressed a little more lightly so it sits neatly on a small base. If you want a plated starter instead of finger food, make the original.
Raw fish is not safe for everyone. Pregnant people, infants and young children, older adults, and anyone immunocompromised should avoid raw fish; at a party, make sure there is a clearly labelled cooked option nearby. Use whole-muscle tuna sold for raw use, keep it below 4°C/40°F until the moment you assemble, and serve it the same day. This is editorial guidance and does not replace your local food-safety rules. See our disclaimer and the complete food safety guide.

Instructions

  1. Make the base (up to a day ahead for wonton cups and crostini). See the three options below. Let wonton cups and crostini cool completely and store airtight at room temperature. Cucumber rounds are cut on the day.
  2. Mix the dressing. Whisk the soy sauce, sesame oil, rice vinegar, ginger and half the lime juice. Add wasabi or sriracha if you like. Keep it in the fridge.
  3. Dice the tuna. Firm the tuna in the freezer for 10 to 15 minutes, trim off any bloodline and sinew, and cut into small, even 1/8- to 1/4-inch (3–5mm) dice — smaller than for a plated tartare, so each bite holds together. Keep it in a covered bowl set over ice in the fridge.
  4. Prepare the garnishes. Slice the scallions, pick the microgreens and toast the sesame seeds if needed.
  5. Dice the avocado no more than 30 minutes before serving, into the same small dice, and toss with the remaining lime juice.
  6. Dress in batches. Right before assembly, fold enough dressing and scallion into the tuna to coat it lightly (a wet mix makes bases soggy), then fold in the avocado.
  7. Assemble. Spoon a heaped teaspoon (about 3/4 oz / 20g) onto each base, or use a small cookie scoop for identical portions.
  8. Garnish and serve. Top with sesame seeds and a sprig of microgreens or a short length of chive. Serve within minutes, on a chilled platter.

Three bases: cucumber rounds, wonton cups or crostini

  • Cucumber rounds (gluten-free with tamari). Cut an English cucumber into 1/2-inch (1–1.5cm) slices — one large cucumber gives roughly 24. Peel alternating stripes for a neat look if you like, and use a melon baller to scoop a shallow hollow in each so the tartare sits in place. Pat dry and chill. They are the coolest, lightest option and the one to choose for a hot day, but they weep, so assemble no more than 15 minutes before serving.
  • Wonton cups. Heat the oven to 180°C/350°F. Lightly oil a 24-hole mini muffin tin, press a wonton wrapper into each hole to form a cup, and brush or spray the edges with oil. Bake for 7 to 10 minutes, until golden and crisp; watch the edges, which catch quickly. They hold the tartare neatly and are the best choice for passing on trays.
  • Crostini. Heat the oven to 200°C/400°F. Slice a thin baguette on a slight angle about 1/4 to 1/2 inch (6mm–1cm) thick, brush both sides lightly with olive oil and bake for 8 to 10 minutes, turning once, until golden and crisp through. A light rub of cut garlic is good but optional. They stand up to the dressing longest of the three.

Whichever base you choose, the tartare itself does not change. If you want heat, swap in the dressing from our spicy tuna tartare, which has its own crostini method, or add diced mango as in tuna tartare with avocado, mango and toasted sesame.

Scaling for a party: 24 and 48 pieces

Allow about 3/4 oz (20g) of finished topping per bite, which works out at roughly 1/2 oz (14g) of tuna each. As a guide, plan on 3 to 4 bites per guest if they are one of several canapés before a meal, and 8 to 10 per guest if canapés are the whole food for a two-hour party (spread across several different canapés). Our portion guide has more detail.

Ingredient 24 pieces 48 pieces
Tuna loin (for raw use)12 oz / 340g1 1/2 lb / 680g
Avocado12
Soy sauce or tamari1 1/2 tbsp3 tbsp
Toasted sesame oil2 tsp4 tsp
Rice vinegar2 tsp4 tsp
Fresh ginger1 tsp2 tsp
Limes12
Scallions24
Sesame seeds2 tsp4 tsp
Cucumber rounds1 large English cucumber2 large English cucumbers
Wonton cups24 wrappers (1 mini muffin tin)48 wrappers (2 tins or 2 batches)
Crostini1 thin baguette2 thin baguettes

Above 48 pieces, don't simply multiply and dress one enormous bowl. Dice and chill the tuna in containers of about 12 oz (340g) each, and dress and assemble one container at a time as trays go out. Buy a little extra tuna (about 10%) to allow for trimming the bloodline and sinew.

Holding time and food safety at a party

Canapés sit out longer than a plated starter, so this is the part of the recipe that matters most.

  • Keep it cold until the last moment. Hold the diced tuna at or below 4°C/40°F — covered, in the coldest part of the fridge or in a bowl nested in ice — until you assemble.
  • Assemble late and in small batches. Assemble only what will be eaten in the next 15 to 20 minutes. This is as much about quality as safety: cucumber weeps, wonton cups soften and avocado begins to brown within about half an hour.
  • Serve cold. Use a chilled platter, or set the tray over a larger tray of crushed ice, and keep it out of the sun and away from the stove.
  • Follow the two-hour rule. Discard any bites that have been out of the fridge for about 2 hours in total — or 1 hour if the room or garden is above 32°C/90°F. Don't return them to the fridge to serve later, and don't top up a half-eaten platter with fresh bites; replace the whole platter.
  • No leftovers. Dressed raw tuna does not keep. Any undressed diced tuna that stayed in the fridge the whole time can be cooked the same day (seared or in fried rice), not saved for raw use.

For more on hosting with raw dishes, see holiday tartare appetizers and our tartare safety checklist.

Prep timeline

  • The day before: bake wonton cups or crostini, cool, store airtight. Mix the dressing and refrigerate.
  • Morning of the party: buy the tuna and get it straight into the fridge.
  • Up to 2 hours before: dice the tuna, cover and chill over ice in the fridge. Cut and chill cucumber rounds. Prep garnishes.
  • 30 minutes before: dice the avocado and toss with lime.
  • As guests arrive: dress one batch and assemble the first tray. Repeat as trays empty.

Troubleshooting

  • Soggy bases. The mix was too wet or assembled too early. Dress lightly, drain excess liquid from the bowl before spooning, and assemble in small batches.
  • Bites fall apart when picked up. Dice smaller and press each portion lightly with the back of the spoon, or use wonton cups.
  • Avocado turned grey. It was cut too early. Toss with lime and cut it no more than 30 minutes ahead.
  • Crostini too hard to bite. Slice thinner and use a narrow baguette so each piece is truly one bite.

Frequently Asked Questions

What is a good tuna tartare with avocado canapé recipe?

Dice 12 oz (340g) of tuna sold for raw use and one avocado very small, dress with soy, sesame oil, rice vinegar, ginger and lime, and spoon a heaped teaspoon onto 24 cucumber rounds, baked wonton cups or crostini. Garnish with sesame seeds and microgreens and serve straight away.

How many tuna avocado tartare bites per person?

Plan on 3 to 4 bites per guest when they are one of several canapés before dinner, and 8 to 10 per guest when canapés are the whole meal (spread across several kinds). 24 pieces serves 6 to 8 people as a pre-dinner bite.

How long can tuna tartare canapés sit out?

Discard them after about 2 hours out of the fridge in total, or 1 hour above 32°C/90°F. For quality, assemble only what will be eaten in 15 to 20 minutes, serve on a chilled or iced platter, and never put leftovers back in the fridge.

Can I make tuna tartare bites ahead of time?

Make the wonton cups or crostini and the dressing a day ahead, and dice the tuna up to 2 hours ahead, kept covered and cold. Cut the avocado and assemble just before serving; assembled bites do not hold.

Which base is best: cucumber, wonton cups or crostini?

Wonton cups are the easiest to pass around and hold the tartare neatly. Crostini stay crisp longest. Cucumber rounds are the lightest and gluten-free with tamari, but they release water, so assemble them last.

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