Place frozen prawns in a large bowl and cover with cold water and salt. Leave for 30 minutes or until defrosted. Drain, rinse and pat dry with a paper towel.
In another bowl mix prawns and chilli garlic sauce until well coated.
Heat your pan, griddle or barbecue. Add the prawns and fry for 1-2 minutes until they turn pink. Do not overcook.
Arrange on a platter, top with spring onion and serve with chilli mayo.