Shred the cabbage.
Thinly slice the onion and carrot.
Heat cooking oil in a pan and stir-fry cabbage, onion, and carrot.
Drain the oil from the canned tuna and add the tuna to the pan. Stir-fry together.
Season with salt, pepper, and soy sauce.
Place cooked rice in a rice bowl and top with the stir-fried ingredients.