Remove mango and pineapple from freezer; let stand at room temperature 10 minutes. Combine mango, pineapple, yogurt, and rind in a food processor; process until smooth. Serve immediately (for soft-serve texture) or freeze in an airtight container for 1 hour 30 minutes (for firmer texture).
I had a problem getting this to blend smoothly in the food processor, so had to add liquid, and the only thing I had on harnd was dairy free coconut milk creamer (for coffee), which actually enhanced the flavor to taste even more tropical. The flavor rates a 4 but because this recipe as written didn't really work (wouldn't blend iwthout additional liquid) I'm giving it a 3