Ratha Chaupoly and Ben Daitz opened the first Num Pang in 2009, a stylish shop that took the basic ingredients of the bánh mì and gave them an elevated Cambodian twist. Earlier this month, to little fanfare, they opened a Num Pang outpost in Times Square — their third new location this year, and their fifth total in New York. In fact, Chaupoly and Daitz have been quietly building a thriving mini-chain, and it sounds like they're ready to break into the big time.