Portway in gocek have an excellent reputation for providing a range of sailing courses, they have English speaking instructors who I have seen in action and would highly recommend.
Whilst the sea and coastline here is stunning and dramatic, a truely wonderful place. The weather however, can be extreme, and certainly no place to be without appropriate skill and knowledge. Enjoy your time afloat, but please take precautions to ensure the safety of yourself and others.