Score each piece of pork lightly with criss-crosses on 1 side.
Mix with marinade ingredients and keep aside, 10 minutes.
Heat oil and deep-fry pork pieces for about 30 seconds over medium heat. Drain.
Drain off all but 2 tablespoons oil and stir-fry garlic and spring onion till lightly browned.
Add water chestnuts and green peppers. Stir-fry briefly, then add seasoning ingredients and heat through.
Add fried pork and mix lightly.