When i first started riding, my hands hurt really bad. But i just dealt with it, and after a few week it eased off. I had some foam grips for a bit aswell, they helped a little bit, but you cant avoid them.
I reckon the reason they are so "tense" is that they arn't concentrating on the move they are trying to achieve, but on how hard they are kicking or how many fingers they are using on the brake. But as they become a lot more confident they begin to forget about braking and kicking, it just comes naturally. This enables them to concentrate on going bigger. I reckon this post probably could help new riders progress a lot quicker
Ask one of your mates to hold ur front wheel up, whilst your on the back wheel, then get used to balancing. Then try it without your mate! Hope this helped