i call it the front wheel/hub nut... and no, you don't need a special tool, you should be able to spin it using a screwdriver. how tight you make it determines wheel preload. if you want to be exact, you'll need a spring scale, attach to one of the wheel lugs, and measure how much force it takes to turn the wheel. IIRC, it should be something like 7 ft-lbs, but I mostly do this by feel now adays.

-Rob