Cook the rice and place it in a bowl.
Dice raw salmon and tuna into bite-sized pieces.
Cut cucumber and avocado into easy-to-eat pieces.
Slice the onion thinly and soak it in cold water to reduce its pungency.
Make a sauce using soy sauce, sesame oil, vinegar, and sugar.
Top the rice with the prepared ingredients, seaweed, wasabi, flying fish roe, etc.
Drizzle the sauce and sprinkle sesame seeds to finish.