Slice the cucumber and carrot into long thin strips.
Beat the eggs, make an omelet, then slice it into long strips.
Mix the rice with salt, sesame oil, and sesame seeds.
Place a seaweed sheet on a bamboo mat and spread the rice thinly over it.
Arrange cucumber, carrot, egg omelet strips, drained tuna, and mayonnaise on top of the rice.
Roll the gimbap tightly.
Slice into bite-sized pieces.