Cook rice in a pan of boiling, salted water about 12 minutes on medium heat. Make sure rice is just tender, not completely soft. Drain well and rinse with cold water. Drain Again.
Mix together next 7 ingredients (pineapple through water chestnuts). Add rice to pineapple mixture and combine well. Season to taste with salt and pepper.
Blend mango puree, garlic, ginger, and soy sauce on medium speed in blender (or by hand, mix well). Slowly pour oil into top of blender, while running, until emulsified. If doing by hand, add oil in a slow stream while mixing constantly.
Once combined, pour dressing over rice mixture and serve.