Cut the pork into bite-sized pieces.
Slice the onion and green onion into thin strips.
In a bowl, mix the pork with soy sauce, red pepper powder, sugar, minced garlic, black pepper, and sesame oil, and marinate for 10 minutes.
Add sesame oil to a pan and stir-fry the marinated pork and vegetables over medium heat.
Once the meat is cooked, remove from heat.
Sprinkle with sesame seeds to finish.