Back in 2006, before I called New York City home, I was here for a visit and on a quest for the perfect margarita. The much-lauded La Esquina had just opened its doors, and I was determined to find a way in. As I learned, gaining entrance to the Mexican speakeasy in Nolita first required the discovery of its well-hidden main door. From there, thirsty pilgrims needed to descend a set of stairs that took them beneath a corner taco stand and then traverse a busy kitchen. Yes, it required some effort, but the hous…