Wash the cabbage thoroughly and slice it thinly.
Cut the tofu into 1cm cubes.
Drain the oil from the tuna and set aside.
Heat cooking oil in a pan and stir-fry the cabbage.
Once the cabbage is wilted, add the tofu and tuna, and stir-fry together.
Season with soy sauce, salt, and pepper.
Serve the stir-fried mixture over rice to finish the rice bowl.