Mix rice with salt and sesame oil thoroughly.
Place a sheet of seaweed on a sushi mat and spread the rice evenly.
Drain oil from the tuna can, mix tuna with mayonnaise to make the filling.
Slice cucumber, carrot, pickled radish, and spinach into long strips.
Layer tuna mayonnaise, cucumber, carrot, pickled radish, and spinach on top of the rice in order.
Roll up the kimbap and cut into bite-sized pieces.