All of my boys went through this stage, the youngest is still there! It is so difficult. I was pregnant when the 2nd one went through it, and not only did it last WAY TOO LONG, but nothing worked to stop him. He just had to grow out of it on his own. We used time outs (which I normally don't use for under 2 year olds, but it was kind of a "last resort" thing) removed him from me (by his daddy -- he hit/kicked mostly me & sometimes his aunt or uncle or someone, but rarely daddy) and he would just come back and do it again. It was funny. It got him attention. I have no idea why.
Now my youngest does it occasionally, hits and laughs and runs off and returns to do it again, but he is easier to deal with.
I have no idea what to tell you, except it seems to be one of those things you have to keep telling them no & why/why it is wrong over & over & over & over before they finally "grow out of" the whole stage.