Cut the pork into bite-sized pieces.
Slice the onion and green onion.
Mix gochujang, soy sauce, minced garlic, red pepper powder, sugar, and sesame oil to make the marinade.
Add the marinade to the pork and let it sit for 10 minutes.
Heat oil in a pan and sauté the green onion to infuse its flavor.
Add the marinated pork and onion to the pan and stir-fry over high heat.
When the meat is cooked, finish by drizzling with sesame oil and sprinkling sesame seeds.