I was there 4 times when I was still windsurfing but I talked to kiters too.
If you know much of this already, perhaps it would be useful as reference to other people.
Kiting is done on both sides of the island but these sides are very different.
Leeward:
Fisherman's Huts -
http://www.aruba-travelguide.com/beache ... M4iTm9WxBkFlat water, quite shallow for a while. The wind can be totally offshore, or side-off. There's plenty of people there for some safety, and usually you can talk upfront about a chase-boat rescue with the guys who run the windsurf rental place, or next door. I understand you can buy rescues for a week as a kind of "insurance policy." It can be crazy gusty in the summer, and the wind can be 30 kts+ in June and July but winters are usually lighter.
Other places on that side do not have rescue boats (at least didn't) so that limits your choices.
Windward:
Boca Grandi
http://www.aruba-travelguide.com/beache ... M4gxG9WxBkThis can be a little hard-core but if you like waves, and prefer the typical safe setup, with clean, side-shore wind, that's the place.
You need a car to get there, and tires get damaged on sharp pebbles on the way in so drive slowly. It's next door to a big, white building of the local prison.
Some people complained about some unsavory characters showing up there but I didn't see any, and the local kiters seemed friendly enough. No facilities there so bring food and drinks with you.
Most other places on that side do not have sand, and the rocks look like some dark fantasy props - thin outcrops, some of them at least 2 ft long, pointing straight toward the sea. This pix shows a mild version of this:
http://www.flickr.com/photos/drljohnson/1684040806/