Becca, when you offer your hand, offer him the back of your tightly clenched fist. He can't get hold of anything to bite and it allows you to not back off from his bite either. This has helped me a lot with my Alexes (the Beaks) - their bills are so darned *big*!
Another great help to me was distracting the bird with a stick or bit of fruit or something as you ask him to step up. The theory is that if his beak's full, he can't bite you - LOL! I've had a few good sessions recently with my pair: we went back to basics ('step up' for a reward) and they're *nearly* at the point of staying on my hand and stepping up when I ask them. Nearly...
Keep us posted on what you do - it's always interesting to hear what works for others!
PS. Clicker training didn't work for us. I just found it too hard to organise the clicker, the treat, the bird and the other bird in my head. I just say 'YES!' at the moment when the bird does what I want and then offer the reward.