Cut the pork shoulder into appropriate pieces.
Slice the onion and green onion thinly.
Mix soy sauce, sugar, minced garlic, pepper, and sesame oil to make the marinade.
Add the marinade to the sliced pork shoulder and let it marinate for about 20 minutes.
Heat oil in a pan and stir-fry the onion and green onion.
Add the marinated pork shoulder to the pan and stir-fry over high heat.
Once the meat is cooked, add a bit of sesame oil to finish.