Blitz the spring onions garlic, turmeric, red curry paste, coconut milk, fish sauce, oil, and sugar together in a food processor or blender.
Add the cilantro/coriander and pulse until incorporated into the marinade. Set aside.
Cut the fish into 4cm pieces, and place into a large bowl.
Pour the marinade over the fish, and stir well to ensure the fish is thoroughly coated.
Marinate the fish for a minimum of 1 - 2 hours, or overnight.
Thread the fish pieces onto bamboo skewers^.
Cook on the BBQ, or on a grill plate, for about 5 - 7 minutes, or until the fish is opaque and cooked through. The actual cooking time will depend on the thickness of the fish.
Serve immediately with steamed rice.