how to take apart 5mW 532nm Open-back Kaleidoscopic Green Laser Pointer Pen

It would be awesome if someone could tell me how to do this.

We can't suggest in much detail how, since there are many different types of pointer constructions, and you haven't posted a picture. Generally, people start with trying to take off the head of the pointer. It is usually glued in placed and could be threaded, so try twisting it with a vice/clamp. Make sure you put a piece of rubber or thick cloth around the pointer if you don't want to leave scratch marks.

This method will not work for all pen style greens. Mine has a different construction and I had to peel the brass casing apart just to get to the module.