# ssh to that machine and authenticate as x

ssh -Y mcyster@mcyster.dev.b0.lt

  sudo -s to  # become root
    export DISPLAY=:0.0
    xhost +
    # exit root shell

  vino-preferences
    # enable sharing

  export DISPLAY=:0.0
  /usr/lib/vino/vino-server  # start vino server

# start you vnc client on the local machine