When my daughter spent a summer in China, she told me about lychees, a pink fruit they would pick and eat right off the trees. I'd never heard of them, but found canned lychees in an international market and began a search for recipes using them. This recipe intrigued me because of the unusual mix of juices in the sauce (tomato, orange, and pineapple). It also calls for chestnut flour, which I've never used, but I've been told it's sold in World Market, Whole Foods, and specialty food stores. This recipe is from the Empress of China Restaurant in San Francisco, California.