Place a small saucepan over high heat, add water and bring to the boil.
Add some sea salt to taste and a tablespoon of oil.
Place the couscous in a small bowl and pour the boiling water over the top.
Cover and let stand for about 5 minutes until all the water is absorbed.
Fluff up the couscous with a fork, set aside in a warm place. When ready to serve, add the tomato, onion, mango and coriander to the couscous, combine well.
Pre-heat the barbecue or frying pan.
Place the prawns onto the barbeque and cook for 2 to 3 minutes.
Turn and cook for a further 3 minutes.
Add a squeeze of lemon to the prawns when you finish cooking them.