In the very first area, after you've picked up the torch and are about to head into the sewer, an explosive hits the wall to the right of the sewer entrance and reveals two pots of gold. How the hell do I climb up and get them? I can't sheathe my sword and I can't put away my torch, and the control config screen doesn't show anything resembling a "climb" control.

You need to jump on top of the door as it's opening then along the bricks sticking out to get up there.