Here's a sweet video of World Cup champion and Olympic silver medalist whitewater slalom kayaker Campbell Walsh in 2007 slaying it on a slalom course.
Notice the incredible directional changes and razor sharp eddy turns, plus a lot of super efficient and effective paddle moves. As the video progresses it just gets more impressive. It's not hard to see why a lot of the kayakers winning Extreme Creeking races have a slalom background!
In case you're new to all of this, K1 is regular kayak style and C1 means the paddler is kneeling in the boat - it's much harder because they're using a one-bladed paddle and their center of gravity is higher. On the course you're supposed to go downstream between the green-striped gates and upstream between the red-striped gates. That's about as much as I know. :)
Having spent a little bit of time getting advice from slalom people I can tell you that they're experts at using even small river features. I think as we progress on the normal scale of learning we figure out how to use obvious river features to let the river help us get to where we want to go, but I was struck by how they'll pick out really small ones and use those very effectively.
Lately I've been heading up when I can to the Tamihi Rapids slalom course on the Chilliwack River, the Chilliwack Center of Excellence keeps gates there year-round and Craig and Jon Allen have been super nice about coming out to give some instruction to me and my friends even though we're in creekboats.
If you're wondering if this kind of practice is worth it, all I can say is that spending a day and a half trying to exactly nail a few gates and ferries on Class I, II and III did more for my technical Class IV skills than years of plowing through Boulder Drop at beefy flows.
Yes, it's important to get used to handling pushy big water, but actually having the skills to get where you need to go is equally important and maybe harder to learn. If you try it out you will probably be amazed at how hard it is to be extremely precise on what looks like very easy water.
Mike and I went up there once when the water was pretty high and the course was pushy, Craig Allen showed us a creeking-style course to shoot for and then greased it in a C1, while Mike (who paddles hard Class V a lot) did well but didn't get the course completely right once. "Humbling" was the word he used.