Thinly slice the pork.
Julienne the onion, green onion, and carrot.
Prepare the marinade (soy sauce, red pepper flakes, sugar, minced garlic, sesame oil, black pepper).
Add the marinade to the pork and vegetables and let it marinate for 20 minutes.
Heat oil in a pan and stir-fry the marinated pork and vegetables.
Continue to stir-fry until the pork is fully cooked.