We had this one summer on Kauai and have been trying to match the simple deliciousness ever since. Then this came to us via Epicurious, originally from Masaharu Morimoto’s “Mastering the Art of Japanese Home Cooking,” and we found the answer. You might have to look a little harder in the store for some of the ingredients, but it’s really worth it.
For 2 fairly large bowls, or x4 smaller bowls as more of a starter, you’ll need: 1 lb sushi grade tuna (we used Ahi; cut into no larger than 1/2″ cubes), 1/4 c soy sauce, 1 Tbsp plus 1 tsp mirin, 2 tsp sesame oil, 2 tsp sweet chile sauce (could be found in the Japanese or even the Thai section), 1 tsp sugar, 2 avocados (cut into 1/2-inch pieces), 2-3 cups cooked brown rice (usually comes from 1 cup uncooked rice; add 1Tbsp rice vinegar after cooking and toss well), 1/2 seaweed sheet, 1/4 c scallion greens (sliced well), 1 tsp toasted sesame seeds.
Start the rice on to bowl – the short and easy method is to place 1 cup rice into 2-3 cups water in a pot. Place the pot on hight heat and cover. Once brought to a boil, set a timer to 20 mins, reduce heat to medium high, slant cover to allow steam to escape, but only slightly. Allow to cook for 20 mins, adding more boiling water if needed. Have a large kettle of boiling water available. Once cooked, strain the rice and pour boiling water over the top to remove excess starch. For this recipe, then add 1 Tspn rice vinegar and toss well.
Combine the soy sauce, mirin, sesame oil, sweet chili sauce, and sugar in a medium mixing bowl and stir until the sugar dissolves.
Add the tuna and avocado to the bowl, toss well, and set aside to marinate for a few minutes but no more than 5 minutes.
Divide the rice among 2 wide bowls. Top each bowl with the tuna and avocado, leaving the sauce behind. Then drizzle the sauce over the tuna and avocado. Tear the seaweed into small pieces and scatter some over each bowl; top with the scallions and sesame seeds.
Mix well in your bowl and eat right away.