The story behind ¡Ay Chiwowa! is well known and pretty funny— local scenetrepreneur Billy Dec saw a chance to buy Martini Ranch, a River North nightspot with a coveted 4 a.m. license, and did so— surprising his partner Arturo Gomez on Twitter. He must have gotten over it, though, since when the concept took a Mexican taco bar bent, Gomez recruited his own father from Mexico City to help devise the street food-inspired menu, which is prepared by the team under executive chef Julio Sanchez Galicia, another Mexico City native who worked his way up through the kitchen at Rockit Bar & Grill (he was one of the very first employees). So while it is, first and foremost, a bar with an extensive lists of tequilas and cocktails, it has a menu of easy-to-like Mexican classics done with an authentic yet contemporary approach— all to make the tequila-sippin’ easier. It opened on Friday; see a few menu items in our slideshow below, and see the menu here.