All the highly rated Indian places do great vegetarian food. Clarksville common has that Bahn mi place where you can their sandwich with impossible meat. Regional usually has done great vegetarian options. Traveling out of HC, look up Ahadu or Tigi for take out (or any Ethiopian places in DC to eat in) for incredible vegetarian and vegan options.

Sorry, but Mexican is lacking, and the ones we have tend to be basic on vegetation and lack vegan