Never fear - there ARE Afro-Cuban dance classes in DC! They may not be advertised well...and there may be just one teacher who is making sure these types of classes are offered, but, they are here and, so I've heard, quite good and fun!
Visit Capitol Movement, Inc. where Oscar Rousseaux teaches every Thursday evening and Saturday afternoon. Go Thursdays for Cuban salsa (Casino, Son, Danzon) and on Saturdays for Afro-Cuban movement (Rumba, Guaguanco, Yoruba, etc.). Oscar is the leader of Alafia Dance and Drum Company and is a highly accomplished dancer and musician.
Check out the Capitol Movement website for information on the exact times of classes and get yourself to a class!