Wash the cabbage thoroughly and slice it thinly.
Slice the onion thinly, and julienne the carrot.
Heat cooking oil in a pan and stir-fry the onion and carrot.
Add the cabbage and stir-fry together.
Drain the oil from the canned tuna and add it to the pan, mixing and stir-frying evenly.
Season with soy sauce and black pepper.
Place the stir-fried mixture over rice.
Sprinkle seaweed flakes and roasted sesame seeds on top to serve.