Here is an official video on YouTube from Kyocera about how they sharpen their ceramic knives. It has almost zero technical details (which is too bad), but it can give you some idea of what they do.
And here is a video (clip from BBC series "How do they do it?") about how Kyocera manufactures their ceramic knives (also short on details, and I think they confuse strength and toughness, but still pretty interesting):
P.S. I didn't learn until later that "Kyocera" is short for "Kyoto Ceramics". Just in case some of you didn't know either!