sudo apt-get install x11vnc
x11vnc -storepasswd
mkdir -p ~/.config/autostart
mcedit ~/.config/autostart/x11vnc.desktop
[Desktop Entry]
Encoding=UTF-8
Type=Application
Name=X11VNC
Comment=
Exec=x11vnc -forever -usepw -display :0
StartupNotify=false
Terminal=false
Hidden=false
x11vnc -forever -usepw -display :0