The term "window bead" is also used for a type of bead that Michael Barley developed. He makes an interesting center of some sort, encases it in clear, and puts dots of very pale aquamarine on the surface and melts them in. He then covers the whole bead in silver leaf, burnishes it in, and burns it off (melts it in -- whatever you call what silver leaf does on clear). The clear reacts with the silver and turns yellowish but the very pale aqua does not, so you get little windows that let you see into the center. Very cool.
For the cold-worked type of window bead, you need a "flat lap," which means a lapidary grinding machine with a flat horizontal surface. They use diamond grinding/polishing disks of different grits for the various steps. You have to use water when you're grinding and polishing.
Here's a link to a page with pictures of some flat lap machines. (No recommendation or anything for these particular machines -- I was just Googling for pictures.)
http://www.gemworld.com/FlatLaps.asp
Here's a link to a page on Lauri Copeland's website that has a picture of some window beads that she's done, as well as some more complicated faceted beads.
http://www.wildfire-designs.com/focalbeads.html