Rinse the rice and cook it.
Julienne the cucumber, carrot, and lettuce.
Cut the seaweed into strips and set aside.
Drain the oil from the tuna using a sieve.
Mix gochujang (Korean chili paste), soy sauce, sesame oil, vinegar, and sugar to make the sauce.
Place rice in a bowl and top with vegetables and tuna.
Add the sauce, then sprinkle with crushed seaweed and roasted sesame seeds.