In order to do this you well need Molotov cocktails and possibly firecrackers. You will also need to unlock the skill that allows you to kick zombies. This can be done anywhere on the map but I've included a screenshot of the exact location that I did it below:
Once you've found some spikes, you'll need a zombie to come near them. Once they are close to the spikes, throw a Molotov cocktail close enough to them to light them on fire and quickly run up to them and kick them (using
) into the spikes. Once they become impaled, the achievement will unlock.