Place the garlic, chilli, oil, lime juice, salt and pepper in a large non-metallic bowl and whisk until well combined. Add the prawns and toss to coat evenly. Cover and refrigerate for 15 minutes.
Heat a grill plate to high. Remove prawns from marinade and thread onto metal or bamboo skewers soaked in water for 30 minutes.
Grill prawn skewers for 2 minutes each side or until prawns are cooked through and golden. Serve skewers with lime wedges and soy sauce, if desired.
