The Darkslide is a really fun, cool looking move to do once you've mastered the mechanics of it! I spent the last few months getting it down.
The first thing you need is GOOD power. The more, the better...I'd say it's a good move for when you are uncomfortably powered! If your juiced, you can really make this move look nice. If you're underpowered it's going to look really lame.
What I do is with good power, I gather as much speed as possible. Then drift the kite from 10 or 2 (depending on direction) over to 12 o'clock. As soon as you are drifting the kite to noon, unweighted from your edge and try to fall on your stomach while keeping the kite in a controlled drift to 12 (slow drift). You'll slide across the water just barely above its surface while your front leg is brought up to your chest, causing the tip of your board to cut through the water. As soon as your speed starts to slow or your kite is passing 12, pull hard with your back hand to initiate a kiteloop that will pull you out of the sliding position and allow you to land switch and ride away in the opposite direction.
Hope the link below works. This was from a day in which we had unreliable side off winds but got some 17mph averages here and there. It's mostly just light wind goofing around but It allowed for the filming of 3-4 Darkslide attempts.
http://vimeo.com/m/43499230http://vimeo.com/43499230