I spent January 2010 in the Southern and Central Coast of Mozambique,
Started my tour in  Ponta do Oura [south Mozambique] - small beautiful town and we had lots of wind, very safe, nice waves and warm water.  Xai Xai, north of Maputo, kiteboarded 5 out of 7 days. At approx. 15h00 the wind starts and blow, up to about 20h00.  Tofo beach, absolute Magic place, water temperature 33 degrees C, Big Bay area, nice waves, also afternoon winds [East]
 Bilene, Flat water, Huge lagoon [Lake], wind every day, Fantastic accomodation [Palmeira Campismo/chalets]
Accommodation, Fish, Prawns, Crayfish [Lobster], Fruit, Beer and Fuel [gas] are cheap and available at all the above places. You will love Mozambique, friends told me Tanzania is very beautiful but the wind is less than Mozambique and South Africa.