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Three fresh Bluefin Tuna Onigiri rice balls served on a ceramic plate.

Bluefin Tuna Onigiri

Forget everything you know about the standard convenience store snack. While the traditional Tsuna Mayo (canned tuna) onigiri is a beloved staple, today we’re taking this Japanese icon to a whole new level.
Meet the Bluefin Tuna Onigiri.
By using fresh, sashimi-grade bluefin tuna paired with a hint of toasted sesame oil and zesty ginger, we’ve transformed a simple rice ball into a gourmet experience. It’s the perfect marriage between the elegance of high-end sushi and the comforting, handheld convenience of a classic onigiri.
Whether you’re looking for a sophisticated appetizer or a refreshing lunch that stands out, this recipe is your gateway to mastering authentic Japanese flavors at home. Let's get rolling!
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Course: Snack
Cuisine: Japanese
Ingredients Method

Ingredients
  

The Rice:
  • 2 Cups Japanese short-grain rice (sushi rice) (300g)
  • 2 ½ Cups water
  • Optional: A splash of rice vinegar, sugar, and salt (if you prefer seasoned sushi rice)
The Bluefin Tuna Filling (Tartare Style):
  • 150 g fresh bluefin tuna (sashimi grade)
  • 1 tbsp soy sauce (Shoyu)
  • 1 tbsp toasted sesame oil
  • ½ tbsp freshly grated ginger
  • 1 green onion, very finely minced
  • Optional: A touch of Wasabi or Sriracha for a spicy kick
For Assembly:
  • 2 to 3 sheets of Nori seaweed (cut into strips)
  • Toasted sesame seeds (black or white)
  • A small bowl of water and fine salt (for your hands)

Method
 

Prepare the Rice
  1. Wash the rice several times until the water runs clear. Drain well.
  2. Cook the rice (ideally in a rice cooker). Once cooked, let it rest for 10 minutes, then fluff it gently. It is best used while still warm.
Prepare the Tuna
  1. Cut the bluefin tuna into very small cubes (about 0.5 cm).
  2. In a bowl, toss the tuna cubes with the soy sauce, sesame oil, ginger, and green onion.
  3. Note: Since the fish is fresh, prepare this filling just before assembling the onigiri to maintain maximum freshness.
Shaping the Onigiri
  1. Wet your hands with a bit of water (to prevent sticking) and rub a pinch of salt over your palms.
  2. Take a handful of warm rice and create a small well in the center.
  3. Place a generous teaspoon of the tuna filling into the center.
  4. Gently fold the rice over the filling to enclose it completely.
  5. Lightly press the rice into a triangle (or ball) shape. Be careful not to squeeze too hard; the grains should stay intact.
The Finishing Touch
  1. Wrap the base of your triangle with a strip of Nori seaweed.
  2. Dip the top or the edges of the onigiri into the toasted sesame seeds.
    3. Freshness: Because this uses raw bluefin tuna, these onigiri should be eaten quickly (within 2 to 3 hours) and kept chilled if not served immediately.
    The Crunch: If you are packing these for later, wait to add the Nori until the very last moment so it stays crisp.
    Variety: You can also add a small piece of avocado or a thin slice of cucumber inside for extra texture and color.