If you get one I would go with the stainless/satin finish which has more longevity in salt water. I've had 2 of the black oxide finish replaced by Benchmade within 6 months of use.
The satin will last longer and its a good idea to rinse with fresh water and apply a silicone spray. Cover the blade with surf board wax which keeps the blade sharp and free of corrosion.
Skydiving knives, sometimes called jack knives work well for kiteboarding.
Here is a link to a page with an assortment of hook knives.
http://www.square1.com/Manufacturers...e1/cat212.html