I had a contractor install a new Price Pfister Contempra shower/tub faucet handle. There is a gap between the flange and the tile of approximately 1/4 inch where I can see the gasket. It looks to me as though mositure/leaks might get through. At the very least I'd expect some sort of mold to grow in there. Tightenting the flange isn't really an option as it's as tight as can be already.
I suppose one could always run a bead of caulk but that doesn't seem to me to be the correct way to address this issue. It seems as though the flange should be touching the tile not separated by a gap. It doesn't look to me to be a clean professional look but I can't see where the contractor didn't follow the installation. Is this normal?
No, it isn't normal. The big escutcheon should fit pretty tight to the tile. Is it loose or will it wiggle? On my PricePhister shower valve, there's a cylindrical retainer that screws onto the valve after the escutcheon is installed and before the handle goes on. The retainer draws the escutcheon tight to the wall.
If your shower has this retainer, I'd suspect that your installer installed the valve body too far forward in relation to the face of the tile. There is a specific range of dimensions that the valve has to be installed within in order for the escutcheon and retainer to work right.
You should not accept the installation as it was done, and should contact the installer immediately to have them re-do their work. There's no realistic or professional way to caulk it and make it work worth a darn for very long.
Once the escutcheon is installed tight to the wall, you should caulk it to the wall with a small amount of clear silicone. I suggest caulking from 7:00 to 5:00, leaving 6:00 (the very bottom) open just a little bit in case any water ever does get back there....Leaving 6:00 open will give it a place to weep out.