A Rubber, Plastic or dead blow hammer will do the trick, or put a block of wood inbetween and hammer away. When U put it all back together make sure your hub is clean and smooth and put some anti-seizing compound on it. That should keep it from seizing on again.
The screws are there for the factory, so when the cars are moving along the assembly line the rotors don't fall off. Just put a lug nut on during reassembly to keep the rotor from flopping around.