This restaurant was introduced to me by the amazing Diane of The W.H.O.L.E Gang. She dragged a large group of us (all either gluten-free, dairy-free, or both) to this little hideaway for lunch in between sessions at a food conference. It isn't in the nicest part of town, but the restaurant itself is clean, modern, and good for a casual or to go lunch (counter ordering, but they bring your order to your table).
The entire menu is gluten-free, because the restaurant specializes in Venezuelan cuisine that focuses around corn and corn flour. They offer arepas (like pitas but made of corn flour), maize'wiches, cachapas, and empanadas along with some soup and salad sides. The menu isn't completely dairy-free, but they have a lot of dairy-free offerings (just ask!), and the food is simly prepared, so it is easy to find a lot of dairy-free options. I tried the Pernil Arepa with pulled pork, tomato, avocado, and aioli. It was delicious, but surprisingly quite filling! Our group sampled the full range of arepas, and all were well received, but everyone agreed, skip the sides unless you have a big appetite, because the main dishes may look modest, but they will fill you up. The prices are definitely fair for SF.
I have only been to the SF location, but you can see their website (below) for a full menu and for more information on the Napa location.
Location: 401 Valencia Street, San Francisco, CA