Cut salmon and tuna into bite-sized pieces.
Dice cucumber, avocado, and carrot.
Place rice in a bowl.
Arrange the prepared salmon, tuna, and vegetables on top of the rice.
Mix soy sauce, sesame oil, and lemon juice to make the sauce.
Drizzle the sauce evenly over the ingredients.
Top with seaweed, sesame seeds, pickled ginger, and other toppings to finish.