Get something with a semi-slick, or "file" tread. The Happy Mediums are really nice. I'm riding the 35c version right now, and using my CX bike for much the same thing as you plan on.
They also come in 32c.
Clement LAS tires are really nice, have a BIG volume for a 33c, and are FAST. Downside? They wear pretty quickly.
Kenda Small Block 8s are pretty good, and come in both 32 and 35c.
Continental, Vittoria, and a few others make file treads as well.
None are "road" tires per se, but all will be much easier to push around than a 40c tire.
The wide rim width will only be an issue is you try to go narrower than 26.5mm. If you want a true road tire, look for something like a Conti 700x28. You could probably get away with running a 25c tire, but it may present problems as the carcass of the tire may not have enough volume to catch the bead properly. The results could be bad...