Janski, I second the Vidalia Chopper, been using it for 1.5 years, with great results. Heres the technique, cut the ends of the onion, remove the skins, lay the onion down on the flat side so that the rings are facing up, cut it into 4ths then take each piece down on the cutter at a time, because the cutter wont handle a whole onion. If you do it the other way, it becomes long pieces instead of diced.
But as far as the Vidalia Wizard, great tool, use it all the time!!!
And breathe through your mouth (not your nose) while chopping and cutting and you won’t shed a tear during the process…