x11vnc

https://www.raspberrypi.org/forums/viewtopic.php?p=108862#p108862

must be done as user, not root

sudo apt-get install -y x11vnc

x11vnc -storepasswd

sudo mkdir -vp /home/pi/.config/autostart

sudo dd of=/home/pi/.config/autostart/x11vnc.desktop << EOF
[Desktop Entry]
Encoding=UTF-8
Type=Application
Name=X11VNC
Comment=
Exec=x11vnc -forever -usepw -display :0 -ultrafilexfer
StartupNotify=false
Terminal=false
Hidden=false
EOF