One of two Runner-Up recipes for 1999 in the San Francisco Chronicle. The recipe comes from Le Colonial restaurant in San Francisco. This granita, with its fiery chile, tart lime, pungent mint and fish sauce, gives a decidedly Southeast Asian flavor to the oysters. A spoon of the intensely flavored ice not only keeps the oysters chilled, but as it melts, it creates a delicious sauce that pools in the shells. The granita is best when made the day before serving.