For the sweet chilli dressing
Thread the prawns onto the skewers and brush with olive oil. Season well.
To make the sweet chilli dressing, place the chilli, vinegar, sugar and garlic in a saucepan and bring to a boil. Remove from the heat and allow to cool.
Stir in the rest of the ingredients.
Prepare a fire of medium-hot coals and grill the skewers for 3-4 minutes on each side.
Serve the prawn skewers with the gem lettuce, sliced avocado, crispy onions, coriander and mint leaves.