Place 1 sheet of seaweed on a bamboo mat.
Press a thin layer of cool rice on the seaweed. Leave at least 1/2 inch from the top and bottom edge of the seaweed uncovered. This is for easier sealing later.
Arrange cucumber, red bell pepper, kimchi, and pork belly to the rice. Position them about 1 inch away from the bottom edge of the seaweed.
Slightly wet the top edge of the seaweed. Roll from bottom to the top edge with the help of the bamboo mat tightly.
Cut roll into 8 equal pieces and serve.