Instructions:
- Place the warm, cooked rice into a large mixing bowl.
- Drizzle the rice evenly with sesame oil and sprinkle with salt. Stir gently to distribute the seasoning without crushing the grains.
- Add the chopped kimchi, crushed seaweed, sliced scallions, and mayonnaise to the rice mixture. If using optional fish, add it now.
- Using a spatula or gloved hands, gently fold and mix all the ingredients until they are evenly distributed throughout the rice. Taste and adjust salt if needed.
- Lightly dampen your hands (or place plastic wrap over them). Scoop about 2-3 tablespoons of the mixture into your palm.
- Gently press and roll the mixture into a compact, uniform ball, roughly the size of a golf ball. Place the formed ball onto a clean platter.
- Roll the finished rice balls lightly in extra toasted sesame seeds or crushed seaweed flakes for texture and presentation.
- Serve immediately while still slightly warm, or chill slightly for packing.