In Chinatown or Curry Hill or Flushing or Koreatown, it’s a simple task to find expats and first- or second-generation immigrants eating authentic dishes from home. But Szechuan Mountain House has accomplished this legitimacy on St. Marks Place, its first expansion outside of Queens. It helps to have above-and-beyond ambience and dishes this tasty. The chili, garlic, fermented vegetables and pork on the string beans is a hat trick of flavor—freshness, spice and umami—reminiscent of mapo greens. The jellyfish salad has a dazzling, surprisingly wet crunch and is a perfect refresher. The short ribs disappoint after pyrotechnic tableside razzle-dazzle, and the accompanying buns are too bland and doughy. But overall, if Manhattan won’t go to the Mountain, we’re lucky the Mountain has come to Manhattan.