1. Using a mortar and pestle, pound garlic and coriander roots into paste. You can use a food processor if you prefer.
2. Place pork pieces in a non-metallic bowl. Add the paste and mix using your hands.
3. In a separate bowl, add soy sauce, oyster sauce, sugar, salt and pepper, coconut milk and corn flour. Mix to combine. Add the marinade to the pork pieces and gently mix them thoroughly using your hands.
4. Cover the bowl, place in the refrigerator and let the pork marinate for a few hours or overnight.
5. Thread a few pieces of pork on the skewer.
6. Preheat the grill or chargrill on medium-high heat. Brush with oil to lightly grease.
7. Cook pork for 5-7 minutes each side or until cooked through.
8. Serve with steamed rice.