For tuna

Cup of Yum
1. Drain the tuna well by pressing firmly to remove more liquid. Mix tuna with minced onion and mayonnaise in a small mixing bowl.

For cucumber

1. Thinly slice the cucumber using a mandolin slicer or knife. Place them in a large bowl, sprinkle salt over the cucumber strips, toss, and let them sit for 5 minutes to draw out moisture. After they've sat, gently squeeze out the excess water. This step ensures the cucumbers remain crisp and well seasoned. Transfer the cucumber to a bowl.

For rice

1. Season the cooked rice by mixing in salt, sesame oil, and toasted sesame seeds in a large mixing bowl.

Assembling kimbap

1. Lay a sheet of seaweed (gim), shiny side down, on a cutting board or clean surface with the longer edge facing you. Evenly spread about 1 cup of rice over the seaweed. If the rice sticks, wet your fingers slightly with water.
2. Place two lettuce leaves at the edge closest to you on top center of the rice, followed by the tuna mixture and cucumber strips on top of lettuce. Add a strip of radish pickle for an extra tangy crunch.
3. Carefully roll the seaweed over the fillings, using both hands to tuck in the ingredients. Apply gentle pressure to ensure the kimbap roll is tight and compact. If you're not comfortable rolling with your hands, use a bamboo sushi mat to firm up the roll.
4. For a glossy finish, brush the roll with a touch of sesame oil and sprinkle with toasted sesame seeds. Before slicing the roll into bite-sized pieces, apply a little bit of sesame oil to a sharp knife to prevent sticking. Cut the roll into 1/2-inch bite sizes. Clean the knife with a damp towel when needed and apply oil again.