You'll need a 1/8" punch (I used cheap flat tipped punches from Harbor Freight), a small hammer (also from HF) and a roll of duct tape works well as a disassembly/reassembly block.

If you're installing the duty/carry kit that comes with a new striker block and spring, you'll need a 1/16" allen/hex wrench to remove the screw and I strongly recommend getting a sight pusher tool.

Some people managed to remove theirs with a brass punch and hammer but, mine was tight as hell and wouldn't budge. I eventually did get it to move but, I boogered it up quite a bit and had to get a new one.
I used one of these and it worked like a charm without leaving any tool marks on the sight or slide.
VISM Universal Pistol Slides Rear Sight Tool Glock Pusher 1911 SIG Heavy Duty