Heat a film of vegetable oil in a large frying pan or wok over high heat. Add the sliced pork and stir-fry for 4–5 minutes until browned and just cooked through. Season with a pinch of salt and pepper. Transfer to a plate and set aside.
Add another film of oil to the pan. Stir-fry the onion, carrot, capsicum and beans for 3–4 minutes until just tender but still crisp. Return the pork to the pan, then pour in the Korean stir-fry sauce. Stir well to coat and cook for a further 2–3 minutes until everything is heated through.
Serve with rice and scatter over the spring onions.