17 Aug 2010 17 Aug 2010
After killing Cliff you get the empty store key. In the empty store there are two books, Survivalist and Wrestling. The Wrestling book gives you a significant boost to your bare-handed attacks.
With the book in your inventory you can kill with one drop kick. Just run around in paradise plaza drop kicking until you get the achievement. I think this is easier than the double lariat which doesn't always work when I want it to, and sometimes leads to being surrounded and chomped on.