Go to the northeast side of the island near Red hook. The Ritz carlton beach in Great Bay is, well, great. Look for a dirt road turn off into Lindquest Beach off Hwy 38 north of Red Hook. Great spot but watch the reef. I'm sure there are other 'secret' spots too.
The wind is mostly onshore to side-onshore. The trades should be good now but were light when I was there, except for two good days. I sailed my 12 when I could but it would be nice to have a full quiver with you just in case. Check the NOAA site for wind forecasts.
There is a Shop in Charlote Amalie near the cruise ships that sells kites and accessories but it is mainly a surfing store. There is also a guy, Dave, I think, In Red Hook, West Indies Windsurfing just before the turn off to the Ritz... He has a school for windsurfing kiting and other sailing craft on the Red Hook Harbour beach.
Have fun you lucky ....!!!!!!!!