Thank you for your suggestion. I managed it by installing x11vnc. To start it i created a systemd unit file "/etc/systemd/system/x11vnc.service":
[Unit]
Description=x11vnc-Server
[Service]
ExecStart=/usr/bin/x11vnc -display :0 -auth guess -forever -loop -noxdamage -o /var/log/x11vnc.log -rfbauth /root/.vnc/passwd -rfbport 5900 -shared
[Install]
WantedBy=graphical.target
With the commands `systemctl enable x11vnc` it will automatically start at system boot. You can also manually start it with `systemctl start x11vnc`
I hope this will work in future SuSE releases.