On Lubuntu: When I get stuck on Flash I use the following script bound to a key (Ctrl+shift+l in my case):

  #!/bin/bash

  # Activate Firefox window
  wmctrl -a "Mozilla Firefox"

  # Move cursor to specified position
  xdotool mousemove 250 50

  # Send a mouse click (left click)
  xdotool click --repeat 2 1