Great news for fans of wang mandoo: Jason Wang’s offshoot of Xi’an Famous Foods — which the Underground Gourmet once honored as a choice Cheap Eat — is moving into the former home of Alder, at 157 Second Avenue. The restaurant will seat 32, with a standing bar, and be open from 11 a.m. until late evening every day of the week. The Biang! spot in Queens will become another location of Xi’an Famous Foods. Stay tuned for an opening date.