I am trying to hang a light fixture on the ceiling of my kitchen. What i have noticed from other light fixtures that I have hung is that it takes a special type of screw (or at least it seems like it) that has a special cut on the top of the screw. What type of screw is this?
If you are replacing an existing fixture, the answer is likely no. What it sounds like you are describing is a thread cutting screw:
These tend to be included with mounting hardware to make it easier to screw them into unthreaded holes in plastic or fiberglass electrical boxes. Unless you are using a new electrical box without threaded holes for the fixture strap (or the attachment points on the strap are not threaded) there is no reason to use them.