Make Kimchi Fried Rice: In a non-stick pan or skillet, heat 1 tablespoon of sesame oil or regular oil over medium heat. Add diced onions and cook for about 3-4 minutes until they are soft. Stir Occasionally.
Add spam and cook for about 1 minute, then add in the kimchi and cook for another 30 seconds to bring out the flavors.
Add in the rice and Gochujang, stir to mix until everything is well combined. Remove from heat and set aside.
Assemble the Kimbap: lay a sheet of nori rough side up on a sushi mat or a clean flat surface if you prefer to not use a sushi mat. Evenly spread 3/4 - 1 cup of kimchi fried rice over the nori sheet, covering the bottom 3/4 of the nori, leaving the top 1.5 inch uncovered. Press down on the rice with your fingers or the back of a spoon to ensure it’s flattened evenly.
Add corn, cheese, and mayo into a microwave-safe bowl. Mix well, then microwave for 1-2 minutes until cheese has completely melted.
Pour 1/3 of the cheese mixture evenly across the top.
Tightly roll the kimbap from the bottom end all the way to the top.
Repeat step 4, 5, & 6 two more times with the remaining nori sheets.
Evenly cut each kimbap into bite-sized pieces. Serve right away & enjoy!