This achievement takes around 5 minutes from booting up the game.
On the very first level, walk up a little bit and there should be a dude with a red arrow over his head standing next to some candles. Walk next to him and the candles and press
to light him on fire. Wait until you see your combo counter go up by one, then pause and restart. Repeat 10 times for an easy achievement.
You'll also probably get the "I just want to get some sleep" achievement if you use this method, since the combo doesn't seem to reset itself when you restart a level. If you don't want this achievement for whatever reason, just wait until your combo expires before you do your next kill.