Kumquats are small citrus fruits with an oval shape and a bright orange skin. Unlike other citrus fruits, the skin of kumquats is sweet and edible, while the flesh inside is tart. They have a unique flavor combination of sweet and sour. Kumquats are often eaten whole, including the peel, or used in desserts, jams, and marmalades. They are known for their refreshing taste and are a good source of vitamin C and dietary fiber.