If it's gnome3, as I suspect, then you are probably using gnome-shell by default, which handles window management and compositing. If you want to compiz, then you need to configure gnome to use fallback mode:
http://www.dedoimedo.com/computers/g...-fallback.html
Once that is done, you can configure gnome to autostart compiz by adding compiz-manager (assuming opensuse packages it) to your session.
Adam