IN Margarita you have got to go to El Yaque... Try Hotel Casa Viento - run by a lovely lady called Morenna. Very friendly, clean, yet cheap...
However there are a LOT of people on the water in Margaritta. Not the best place to learn to kitesurf. Possibly better to get the little ferry from El Yaque across to the even smaller island and hour away - a lot more private and easy to learn, and if you are going with your girlfriend, it is a noicer place. SOrry, can't remember the name of the island but you can't miss it.
However, I would more highly recommend Ras Sudr in Egypt. Fab for pros, and absolutely top notch for beginners. I used to windsurf, and always resisted learning to kitesurf, even in Margaritta... but when I went to Ras SUdr, it was sooo good I thought if i am going to learn anywhere it has go to be here.
There is a web page for it - something like...
www.surfegypt.wordpress.com i think, or maybe .co.uk, not sure. check it out
WHerever you go, have fun, good luck
Anton