Try and get large raw head on prawns as they look fab. You can often get these frozen. If you can't get those just get the biggest raw prawns you can. Clean the prawns beforehand and keep covered in the fridge, prepare the other ingredients and put it together just before guests arrive and then it only takes 10 minutes or so to cook.
Give everyone hot finger bowls with lemon in as it is messy.
Serve with hunks of fresh bread for mopping up the juices, sour dough is delicious with this dish.
Don't over power with the chilli sauce, it should have a good balance of strong flavours but the chilli should not be overpowering.