I ride all the time in Keen sandals. I've never been so comfortable riding. I have Crank Brothers 5050x pedals on my Surly LHT. Nice wide and flat surface. Picked them up on sale. On my recumbents I do use clipless pedals (Crank Brothers Eggbeaters) and use them with cycling sandals. I find sandals are much more comfortable for my feet then any shoe, give them a try. Your feet will be cool and comfortable no matter how hot it is. When its cold (and it still is here in Vermont), I just slip on a pair of wool socks with the sandals and I'm good to go.

Brian