Kra Chai is also called Fingerroot, Lesser Galangal and Chinese Keys.
Kra Chai is a relative of ginger, and is renowned for its sweet taste and peppery bite. While kra chai may offer less of an aromatic bouquet than ginger, it has an unusual lemony aspect.
Kra Chai is mostly used in Southeast Asian cooking, particularly in soups and coconut milk-based dishes. It makes an excellent ingredient for stock, as well as chutney.
The rhizomes are commonly used as vegetables in main dishes or eaten raw when young. It is also popularly used in flavorful curry dishes.
Krachai is generally either grated (most common) or sliced very thin for use in recipes. You can scrape the skin off if you wish but it hardly seems worth the bother. It is most commonly used in curry pastes and as an aromatic vegetable.