Simply turning the prop in the reverse direction will make it push instead of pull, but the thrust will be substantially lower. That is because props have cambered airfoils. It's like flying an airplane with a flat-bottom wing upside down, it works, but not as well as right side up. By mounting the prop backward and turning it in the reverse direction, the airfoil shape is correct for the thrust direction.
Gas engines are not easily reversed so they need special pusher props that have a left hand pitch instead of a right hand pitch.

The only difference between pusher and tractor is the motor is in front of the prop instead of behind it. It shouldn't affect thrust much. Pushers tend to be a lot noisier than tractors because tractor props get clean un-disturbed air and pushers get the wake of the stuff that is in front of them.