Cut the aged kimchi into bite-sized pieces.
Slice the onion and green onion.
Heat cooking oil in a pan and stir-fry the green onion to release its aroma.
Add the aged kimchi and onion, then stir-fry together.
Season with sugar and soy sauce.
Add a little water and continue stir-frying over medium heat.
Finish with sesame oil and sesame seeds to your liking.