I am looking for a fresh fruit. It is originally from Central America and is known there as Pitahaya. The French took it to Viet-Nam where it became very popular. From there it was taken to Taiwan and possibly southern china, I'm not sure. The link below is a page with pictures of the fruit.
My guess is a good Salvadoran or Central American market, or a good Vietnamese market. Has anyone actually seen this thing there? (fresh preferred).