Somebody talking good, solid English in Spanish ATC would most certainly be a great addition
Before the thread drifts... You are saying you have family there, but I assume you do not hold a Spanish passport? For any work you will either have to apply for a work visa (not too likely to get as there's plenty of Spanish pilots / ATCOs), or already have the right to live & work there, i.e. a passport.
Other than that it's just about as easy as for a European to get a work permit for the US being a pilot. Sorry I'm not of much help here.