Cut the pork into bite-sized pieces.
Slice the onion, green onion, and garlic thinly.
In a bowl, mix gochujang (Korean chili paste), soy sauce, red pepper powder, minced garlic, sugar, and sesame oil 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 green onion and garlic to bring out the aroma.
Add the onion and marinated pork to the pan and cook over medium heat.
Once the pork is cooked, add sliced hot green peppers and stir-fry once more.
Transfer to a plate and serve.