What torture did Hitler perform on the Jews?
Hitler himself didn't really personally do much of anything in the way of "torture". He was much more interested in eliminating them (and confiscating their property, or in using them for slave labor) than torturing them.
Of course, that also meant he didn't object too strenuously if someone else wanted to torture them in the process provided that his goals were met. He did authorize or at least tacitly allow others to engage in behavior that could be considered "torture"; Josef Mengele being one of the prime examples of someone who used the fact that the government really didn't care too much about the details as long as more Jews were going into the camp than coming out of it.