read /etc/inittab. There may be a line at the bottom
Code:
# Runlevel 4 used to be for an X window only system, until we discovered
# that it throws init into a loop that keeps your load avg at least 1 all
# the time. Thus, there is now one getty opened on tty6. Hopefully no one
# will notice. ;^)
# It might not be bad to have one text console anyway, in case something
# happens to X.
x1:4:wait:/etc/rc.d/rc.4
it'll probably be runlevel 5 for your suse. But read where the script is and it'll probably have commands on what it starts for your window manager. For me, I just edit what's on that line to change my login manager.
There's probably a point and click GUI method someone may know. suse probably has a tool for that.