I've thought to play a very showoff piece that isn't very difficult, something like Chopin's Fantasie Impromptu, but this is very overplayed.
As I'm spanish, I've thought playing some Albeniz, but well, I'm open to suggestions.
Gottschalk's Souveniers D'Andalousie and Moskowski's Caprice Espagnole are brilliant and effective works, but require good repeated note technique.