Whisk ingredients together and season with salt and pepper to taste. Refrigerate until needed.
In a medium mixing bowl, toss the prawns with 2 tablespoons of the dressing to coat and set aside. Add remaining salad ingredients except for lime wedges to the bowl and toss with remaining dressing. Cover and chill well.
Divide the chilled fruit mixture among 4 stemmed cocktail glasses or small bowls. Top with the prawns (4 or more per serving) and garnish with wedges of lime.
Salad ingredients should be prepared up to 1 hour in advance and refrigerated until ready to serve.
Serve this Tropical Shrimp Cocktail as a refreshing starter or main course.