Prepare oatmeal, tuna, and kimchi.
Finely chop the kimchi.
Heat sesame oil in a pot, then stir-fry the chopped kimchi and tuna.
Add water and oatmeal, and bring to a boil over medium heat.
When the kimchi and oatmeal have softened, season with salt and pepper.
Serve in a bowl and top with seaweed flakes or green onions if desired.