Not easily, its wired up to the mains, and really does shut off the power to the PSU so that you can prevent "vampiric drain". Amusingly its a throwback to when computers had proper, manly power switches.
The "lets totally bypass the switch" method involves opening up the power supply, cutting or desoldering out the leads to the switch, and connecting them. This is a bad idea since if you don't do a perfect job, things could get loose.
I'd probably see if I could finagle a suitably sized cover (hell, cardboard and tape may do the trick. Alas, I can't find any suitable missile launch style covers, though some emergency switch covers on alibaba look interesting!), or glue it in place while switched on - hot glue would be a good reversible solution, or good non metal epoxy - metal and current do not mix.
Alternately move your desktop or see if you can install your PSU upside down. Or put a box or sheet of something between you and the switch. Its very hard to kick the PSU switch, when its usually on the top right hand or bottom left hand corner of your case. Mirror the underdesk!