Clean and prepare the squid, then cut into bite-sized pieces.
Slice the onion and green onion as well.
Heat cooking oil in a pan and stir-fry the squid.
Add the onion and green onion, and stir-fry together.
Season with gochujang (Korean chili paste), red pepper powder, soy sauce, minced garlic, and sugar.
Continue stir-frying over medium heat until the ingredients are cooked through.