I have been travelling to Leros for years, well, since 1992. I always stay in Xerocampos in the south of the island at a small family concern called Villa Alexandros, which is set in a beautiful garden and is a very short walk down a dusty track to the beach.
There are 4 tavernas there, my favourite being "Aloni" but I havent seen wind surfing there. In fact the bay is warm and tranquil and shallow for quite a distance.
Alinda is possibly the place for that, although I don't spend much time there as it is too busy for me, although it is still pretty quietish.
Agia Marina has some nice cafes and zakaroplasteo and an internet cafe.
Up the hill in Platanos is Mike's bakery (great spanokopitta) There is a bus service in the summer 4 times a day which visits xerocampos, Lakki, Agia Marina, and Alinda then goes to Blefouti up near the airport.
You must walk up to the Kastro and see the view, even if you did it before.
It's my favourite island