It's certainly is nice to see so much interest in Flamenco and Tango. A few suggestions...
"Two Cries of Freedom". Every other year since 1997 the Spanish government sponsers a contest to decide who are the best inmate singers of Flamenco within its prison system. Inmates from all over the country enter in these contest. In 1997 there were two winners, Jose Serrono, from Seville and Antonio "El Agujetas", son of famous Flamenco singer "Agujetas de Jerez" and grandson of "Agujetas the old". Serrono was serving a 25 year prison sentence for murder, and "El Agujetas" was serving a 15 years for possesion and distribution of drugs. The contest was so moving that the Spanish government and the Ministry of Culture allowed the two to record their talents under the guidance of master Flamenco producer Jose Delgado. The rest was kind of history. Oh, I almost forgot, the prize for winning the contest. Originally it was just to be 5000 pesetas, but because of the fame that Serrano and "El Agujetas" received the Spanish government decided to grant the two artist there freedom. Hence the titile.
This is a truly great recording. RIOR records ruscd8246.
Manolo Caracol, "Grandes Cantaores Del Flamenco"
A well performed charming recording. Ploygram Iberica 522087-2
Paco Pena, "Art of Paco Pena" a great master
Pepe Habichuela, "A Mandeli". Hard to find.
Rafeal Riqueni, "Alcazar De Cristal"
Sabicas, "Flamenco Fiesta"
Ramon Mantoyo, "Ramon Mantoya"
Uncle of famed Flamenco guitarist Carlos Mantoya on Chant Du records.
Tomatito, "Barrio Negro". New Flamenco well performed and very interesting.
Jarrez, can't remember the title, but very interesting
Also, Latcho Drom(I think that's the correct title) a soundtrack from the documentary. A recording/movie which tracks this art form from its roots in India to the European continent and beyond.
On the Tango front, I don't know much...almost everything that Piazzola did was fantastic. There is a cool group out of France called Gotan record titled "Project", very fun...kind of Tango trip hop fusion. Might be hard to find. Anyway, I hope this helps. Enjoy!