There are any number of quick lunch options for busy downtown office workers, so there’s hardly a need to queue up in a line out the door for quick grab-and-go. Yet, dozens upon dozens of curious, trend-chasing San Franciscans have been descending upon Eatsa, a new fast-food restaurant located in SoMa’s Rincon Center that opened its doors this week. Instead of the typical interpersonal interactions that come with restaurant dining, there is no human contact required here. According to co-founders Tim Young and Scott Drummond, Eatsa, now open weekdays from 11 a.m. to 5 p.m., is setting out to reinvent fast food. Drummond has a background in marketing and is the CEO and founder of Forty-Forty, an international branding agency that’s worked with a variety of restaurants and resorts including Pomodoro and Oakville Grocery. A single Eatsa attendant roams the streamlined, modern cafe to help the technically challenged diner who might have a difficult time deciphering the ordering system. […] the diners didn’t even interact much with each other.