The décor, such as it is, leaves much to be desired. And the mood, as set by the glum slurpers who patronize the place, is as cheerful as a July 4 picnic at Guantánamo Bay. But this tiny Lanzhou-style hand-pulled-noodle specialist offers one of the most delicious bowls of noodle soup in Chinatown for an absolute pittance. Try No. 2, or “Hand-Pull Noodle w. Beef In Hot & Spicy Soup” — about a quart of deeply flavored, sinus-clearing broth with an anchor of perfectly chewy spaghettoni-size noodles. Another delicious bargain: ten hot and hefty zheng jiao (meat-stuffed dumplings) as wrinkled as prunes and emitting a cartoon trail of steam as they’re portaged from kitchen to table on a Styrofoam plate.