Eh...well I think you are talking about Warwick Davis. In ROTJ he played Wicket. In TPM he played two roles, Wald, that rodian kid that was friends with Anakin, and some unnamed gambling guy that was friends with Watto in the podracing stadium.
Of course there's Kenny Baker in R2 D2 in both movies, as well as Tony Daniels.
I guess Ian McDiarmid played Palpatine in both movies too.
Any of these correct?