Now, against all odds, Siberia is back. And fittingly, it has tunneled its way into yet another underground space: the Turnstyle Underground Market at Columbus Circle, hidden just steps from the 57th Street-Eighth Avenue subway entrance. It opened quietly last weekend, still labeled as "Gotham Taco" (the space's former tenant), but regulars knew where to look. A red glow, a jukebox and the familiar grin of proprietor Tracy Westmoreland, Siberia's self-proclaimed "minister of propaganda," confirmed the resurrection.