Avocet Duro Plus is the only 32mm slick that I know of. Probably a good tire.

I had a pair of Michelin Dynamic 32's that were almost slick. These are cheap tires (<$15), but don't seem like they have flexible sidewalls (low rolling resistance). In a strange coincidence, my rear Dynamic developed a bulge, and I am currently running a 28mm Hutchinson Flash. (I think it's closer to 25 in reality). Also a cheap junky tire.