We still don’t know who’s behind the design of the upcoming and controversial Union Square restaurant, but we do know who’ll be cooking there: chef Don Pintabona of O-V Hospitality Group, formerly of Tribeca Grill. In exchange for running the restaurant, O-V Hospitality has to invest $1.1 million in its construction. The design will “integrate historic elements of Union Square,” be called City Farm Cafe, and open in spring 2012.