Prepare rice and place it in a bowl.
Cut raw salmon and tuna into bite-sized pieces.
Slice vegetables such as avocado, cucumber, and onion into easy-to-eat pieces.
Make the sauce with soy sauce, sesame oil, lemon juice, and sugar.
Place the fish, vegetables, seaweed, and other toppings on the rice.
Drizzle the sauce over and top with sesame seeds or mayonnaise.