Finely chop the red onion and set aside. In a frying pan, heat the oil on high and cook the pork for 6-8 mins, mixing the pork with a wooden spoon to break up the mince. Mix in the green curry paste and 2 tbsp water, then cook for 2-3 mins.
Remove from the heat. Stir in the red onion, lime juice, oyster sauce and herbs. Spoon the pork into the lettuce leaves and serve.