Remove the filling from the aged kimchi, wash it thoroughly, and squeeze out the water.
Drain the oil from the tuna using a sieve.
Chop the aged kimchi finely, stir-fry with sesame oil in a pan, then let it cool.
Mix rice with salt, sesame oil, and ground sesame seeds thoroughly.
Place a sheet of seaweed on a bamboo mat and spread the rice evenly.
Add stir-fried kimchi, tuna, carrots, cucumber, pickled radish, and spinach on top.
Roll it tightly and slice into bite-sized pieces.