Cut the cucumber and carrot into thin strips.
Drain the oil from the tuna using a sieve.
In a bowl, mix the tuna with mayonnaise and salt.
Place a sheet of seaweed on the sushi mat and spread the rice thinly over it.
Arrange cucumber, carrot, and tuna filling on top of the rice.
Roll the kimbap tightly.
Slice into bite-sized pieces.