In the liner notes to the Buena Vista Social Club album which I found on the Internet (will post the link here when I can find it), the description for the Compay Segundo(Francisco Repilado) song Chan Chan says he took inspiration for the song from a folk tale/song told in rural Santiago de Cuba.

I've been searching around for any references to the folk tale, but found nothing except more references to the album and statements like "Chan Chan and Juanica were folk characters." The PBS Buena Vista Social Club site says "The two central characters 'Juanica' and 'Chan Chan' are legends of Cuban folklore." Does anyone know anything about this?