Cut the pork, onion, and green onion into bite-sized pieces.
In a bowl, mix gochujang (Korean chili paste), soy sauce, sugar, red pepper powder, and minced garlic to make the marinade.
Add the marinade to the pork and let it marinate for 10 minutes.
Heat cooking oil in a pan and stir-fry the pork.
Add the onion and green onion and stir-fry together.
Once the pork is cooked, add sesame oil and stir-fry once more.