In a large mixing bowl, combine cooked short-grain rice, sesame oil, soy sauce, gochujang, and garlic powder. Mix thoroughly until well-coated.

Add chopped kimchi, sesame seeds, roasted seaweed flakes, and chopped green onions to the rice mixture. Stir until evenly distributed.

Wet your hands to prevent sticking, then scoop out a portion of the rice mixture and shape it into a round ball. Repeat with the remaining mixture.

Optionally, roll each rice ball in additional sesame seeds or sprinkle with seaweed flakes for garnish.

Enjoy the rice balls immediately or store in an airtight container in the refrigerator for up to 2 days.