Sarita's
Sarita's, 2794 Graham Road, Falls Church, VA, 703-533-9448 (Metro Trip Planner - opens in new window) [Washingtonian | City Paper | Yelp]
Authentic, to say the least. Plus you can find Sarita’s II in the Culmore Shopping Center on Rt. 7, west of Bailey’s Crossroads: 6013 Leesburg Pike, Falls Church, VA, 703-820-2700 [Yelp]
A good rule of thumb is the following: just about every El Salvadorean place in the area is worthwhile if you order well. Which means getting the pupusas. In Sarita’s II they dress the waitresses to maximize the number of leering male customers, so beware if you go.