Cut the pork leg into bite-size pieces.
Julienne the onion, green onion, and carrot.
In a bowl, make a sauce by mixing soy sauce, gochujang (red chili paste), gochugaru (red pepper flakes), sugar, minced garlic, and pepper.
Add the sauce to the pork and marinate.
Heat cooking oil in a pan and stir-fry the onion, green onion, and carrot.
Add the marinated pork leg and stir-fry together.
Stir-fry on high heat until the meat is fully cooked.
Finish by drizzling sesame oil and sprinkling sesame seeds as desired.