This Loop newbie is doing the classic hot-dog-stand thing: Chicago-style dogs and cheese fries served quickly and eaten just as fast, whether at stools or a standing-only counter. The difference? This place is doing it right, doling out natural-casing Vienna Beefs topped with a crunchy pickle, hot sport peppers, juicy tomatoes and neon relish galore. Merkt's cheddar on the greasy fries was dry and pastelike, but U.B.'s "dipping sauces"—in flavors like chipotle and sun-dried tomato—give the divey place a little gourmet touch.