Finely chop the cabbage.
Drain the oil from the canned tuna using a strainer.
Stir-fry the cabbage with a pinch of salt in a heated pan.
Once cooked, transfer the cabbage to a bowl and let it cool.
Mix the cabbage and tuna together, then season with mayonnaise, salt, and pepper.
Spread a thin layer of rice over the seaweed.
Add the filling (tuna and cabbage mixture) on top.
Roll up the gimbap tightly.
Cut into bite-size pieces.