Systematic banks of flamethrowers, lasers (pew pew), or Masers (microwave laser, their heads pop like peeps!) would be the best, the flamethrower systems could provide the initial coverage while the Maser system was built by my ragtag motley crew of post-apocolyptic chums.
Never use flamethrowers. Never.
Zombie coming at you
Use flamethrower
Now flaming zombie coming at you