Place the prawns oil and lemon juice in a shallow dish and toss together set aside to marinate. For the aioli crush the garlic and sprinkle over the salt rub to a smooth paste with the edge of a knife set aside. Whisk the egg yolk and mustard and whisk together in a large bowl. Slowly drop by drop whisk in the olive oil until it is all added and a smooth mayonnaise is formed. Stir in the garlic and lemon juice and plenty of ground black pepper.
Cook the prawns over hot barbecue coals or a hot griddle pan for 6-8 minutes turning once until charred on the outside and cooked through.
Serve with the aioli and wedges of lemon and a few salad leaves.