I built a new system and then installed Linux (OpenSuSE), but now I have a problem..

I really don't like KDE, GNOME, or UNITY. Each one of them feels really overbloated and there's too much not to like about them that I don't care to use them if I don't need to. From the little bit that I've use XFCE and lxde, I really didn't like them either.

So, I started experimenting with Window Managers to find one that would work the best for me. I really liked Window Maker after I tried it.

The big problem now is that I'd really like to be able to use dual heads with it. I have an older NVIDIA PCIE dual output graphics card that I'm using with my unit until I can buy a newer faster one. Even though it's old, I'd still really like to take advantage of it.

Is there a way to do this with WindowMaker?

there certainly is, certainly is, I do it all the time, there should be nothing special you need to do to make it work, it should just work out of box

and yes, WindowMaker IMHO is a nice lightweight WM.