Wash the napa cabbage thoroughly and slice it thinly.
Finely chop the onion and carrot.
Heat cooking oil in a pan and stir-fry the onion and carrot.
Add the napa cabbage and stir-fry until it softens.
Drain the oil from the canned tuna and add it to the pan.
Add the rice and stir-fry everything evenly.
Season with soy sauce, salt, and pepper.
Serve on a plate and sprinkle roasted sesame seeds to finish.