Prawns: In a medium-sized bowl, combine all the ingredients. Cover and refrigerate for up to 6 hours to allow the flavors to infuse.
Salad: Cut the cucumber into small cubes and place in another medium-sized bowl. Add the remaining ingredients. Set aside.
Preheat the barbecue grill to medium. Thread the prawns onto metal skewers, place the skewers on the grill and brush with any remaining marinade.