Prepare the filling ingredients: Slice the crab meat, yellow radish, and flatfish cake. Whisk the eggs and cook in a pan in a single layer. Then, slide the egg onto a plate and cut it vertically, ensuring that the items are cut into thin, long strips.
Prepare the kimbap rice: Next, cook the white rice separately. Transfer all the cooked rice to a large bowl and add sesame seed oil, salt, and white vinegar. Some Asians prefer to use day-old rice; however, fresh rice will serve the same purpose, especially if you're short on time. Put on a food-safe glove and massage the rice with the added ingredients. Keep tasting the rice to ensure that it is well-seasoned with salt.
Layer the ingredients: Place the kimbap roller on a chopping board. Then, place the kimbap seaweed on the roller. The rough side of the seaweed will face upward. Thinly spread out the rice across the seaweed in the middle zone. Add enough rice to cover the seaweed, but avoid a thick layer of rice, as the Kimbap will be a challenge to roll. Then, add each of the remaining ingredients on top of each other.
Roll the Kimbap: The roller encircles the filling ingredients with the seaweed. Press down with your hands and fingers to apply slight pressure around the Kimbap. Roll and press until the rice roll's seaweed is entirely enclosed
Slice the Kimbap to serve: Brush the sesame seed oil on top of the Kimbap. Slowly slice the Kimbap back and forth into bite-size pieces. Sprinkle sesame seeds and serve with Kimchi or ginger pickle.