These are used throughout Asia in soups, spring rolls, cold salads, and stir-fries.
They're similar to bean threads, only they're longer and made with rice flour instead of mung bean starch.
Before using, soak the dried noodles in hot water until they're soft (about 15 minutes), then boil them briefly (from 1 to 3 minutes) and rinse with hot water.
You can also deep-fry the dried noodles until they're crunchy and then use them in Chinese chicken salad, or as a garnish or bed for sauces.