Asonancias is a Spanish poetic term for vowel rhyming, rather than rhyming of consonant plus vowel. I have interpreted it as a kind of multiple variation, where the material is seen as one would view a diamond – rotating it to look at its many sides.
The first movement is fiery and quite rubato. The second is a Cuban moto perpetuo. The last one is very tender and uses the violin as a harmonic instrument.