Place the rice, water and curry powder in a medium pot. Set over medium-high heat and bring to a boil. Cover, turn the heat to its lowest setting, and steam rice 15 minutes, or until tender. Spoon and spread the rice on a wide plate and cool to room temperature.
Transfer rice to a bowl. Add remaining ingredients, except prawns and 2 Tbsp. oil, and toss to combine. Cover and refrigerate salad until ready to serve. (Can be made a few hours before needed.)
Preheat barbecue or indoor grill to medium-high. Toss salad again and then arrange in a decorative dish. Toss prawns with the 2 Tbsp. oil; season with salt and pepper. Grill 1 to 2 minutes per side, or until cooked through. Arrange prawns on top of the salad and serve.
Note: When draining the pineapple tidbits, save the juice and use in this recipe.