Wash the napa cabbage thoroughly and cut it into bite-sized pieces.
Finely chop the onion and carrot.
Heat oil in a pan and stir-fry the onion and carrot.
Add the napa cabbage and stir-fry together.
Add the tuna and stir-fry together.
Add rice and mix well while stir-frying.
Season with soy sauce, salt, and pepper.
Transfer to a plate and sprinkle with sesame seeds.