When my daycare kids are having trouble sharing something I take it away and put it on a high shelf where they can see it but can't get it. They learn very quickly that if we don't share the toy no one gets it.
. I do this too; works great!
Children are great imitators.
So give them something great to imitate.
At 2 he's really not old enough to understand the concept of sharing. His take on it is that "sharing" means he has to miss out. He also doesn't have the verbal skills yet to argue his case, so he uses his body instead. Add to that the fact that toddlers have absolutely no impulse control, and you have a tiny tornado on your hands.
What usually works at that age is redirecting. Taking his hand and saying "no hitting, hitting hurts!" (or kicking, or whatever it is he is doing) and then take him to another activity. With my youngest (18 months) it's harder to get him to accept the redirect than it was with my girls, but he has a bit of a temper. Making him laugh is almost always successful.