Remove cabbage leaves and blanch them briefly in boiling water.
Drain the oil from the tuna can and set aside.
Mix cooked brown rice with tuna, chopped carrot, chopped green onion, salt, and pepper.
Place an appropriate amount of the rice mixture on a blanched cabbage leaf and wrap it up.
Place the wrapped cabbage in a lightly oiled pan and roll over medium-low heat.
Sprinkle sesame seeds on top to finish.