Hi @chrisp, thanks for your interest! I am afraid at this stage, hand swipe gestures would require an additional IR camera (in conjunction to the eye tracking cameras) to be operational and so for now this would necessarily depend on a third party to develop hand swipe features on combination with extra hardware.
For your interest, such a setup was created using a Tobii eye tracker as part of a Graduate these of which you can read further details @ http://www.diva-portal.org/smash/record.jsf?pid=diva2%3A1088409&dswid=-4211
Perhaps if you contact the author they may be amenable to sharing their code with you? Do let us know how you get on.