Prepare the barbecue for indirect cooking over medium heat (190°C to 230°C). If using a Weber Q barbecue, set up your barbecue with a convection tray and a trivet.
Ensure all scales have been removed from the fish. Using scissors, trim the pectoral fins off the fish (optional).
Cut 3 tor 4 diagonal slashes along each side of the snapper, approximately 1cm deep and 2.5cm apart.
In a bowl combine the light soy sauce, lemon grass, chilli, ginger, lime juice and coriander. Reserve any fresh ingredient offcuts for the cavity of the fish.
Lay the fish onto 3 layers of alfoil. Fold up the sides of the alfoil to create a ‘boat’ for the snapper.
Rub the herb mixture onto both sides of the fish, into the incisions and place the remaining into the cavity along with any of the fresh ingredient offcuts. Lay the lime slices over the fish.
Roast the snapper over indirect medium heat for 25 to 35 minutes or until cooked through.
Whilst the fish is cooking, make the coconut rice. Thoroughly rinse and drain the rice. Place the rice, water, coconut cream and ginger in a Weber Q Large Casserole Dish (with lid on- vent open) and bring to the boil over direct high heat, stirring as required. Reduce heat to a simmer and gently simmer for 15 to 20 minutes. Once cooked, remove the rice from the heat and leave to stand with the lid on for 5 minutes. Stir through the reserved lime zest.
Serve the Vietnamese snapper with the coconut rice.