M.P.
You can't refinish particle board but you can paint it. You can paint it a solid color or use one of the different effects that they have out now. Examples would be to layer one color on top of another and wipe part of it away or to antique it.
The dark ones that I've seen included painted black and grey ones. They didn't look like wood. ie have a grain showing thru. One did look like particle board.