Spain has a vibrant folk music scene with a lot of dance music. Most are familiar with the Arabic influenced flamenco music from southern Spain but there is a lot of music from the north, too, including Celtic music from Galicia and Spanish folk dances from Asturias.
Danza and Polca de Silvina are two Spanish tunes I learned from a group called Citania and which I recorded on the CD The Janissary Stomp with Chipper Thompson: http://www.janissarystomp.com
These are both in a 2/4 polka rhythm and are a blast to play. They are pretty straight forward tunes and if you've had any experience with Irish polkas then you'll feel right at home with them.
My only technical advice for these is to play every 1/8th note with a downstroke, even if there are two in a row, and to begin every sequence of 1/16th notes with a downstroke as well. That way all your picking will come out even.
For instance, with Danza, pick the first two bars: D DU D DU DUDU D D
In Polca de Silvina, pick the first two bars: D DU DUDU D DU D DU
If you are not used to strict alternation in 2/4 and 4/4, some of the string crossings might be a bit of a challenge, but work through the sequence slowly and see how it goes. Soon you'll be zipping through these tunes very smoothly.