I'd like to say this is 'quick and simple,' but it is neither. Thankfully, here are some tips to make it a bit quicker and a little bit more towards the 'simple' end of things.
First off, this achievement requires you to set your difficulty to Hard. It does not stack with the Legend one, so don't get your hopes up.
Max out yours and decrease the CPU's.
Love him or hate him, you'll love him during the duration of doing this achievement. Use him because he's a powerhouse and will quickly do damage to each of your opponents.
Woman's Toe Kick, Big Boot, Big Splash, RKO.
Edit Khali's moves. Woman's Toe Kick will damage all body parts and combined with Khali's power, Khali kicks most ass while kicking like a woman, apparently. Start your match by doing this over and over until most limbs are red, then do a big boot. More than likely, you'll bloody your opponent, but this still isn't enough to score a win. Use the Big Splash instead of a regular pin, as it's a high damage move with a pinning combination. It'll also give you a finisher (in case they kick out) if you have the Smackdown meter fill settings on highest, so give Khali an RKO finisher for a quick nail in the coffin, but you'll rarely need it except for fellow tanks like Batista or Triple H.
That's about it. Make a list, grind it out. As far as I know, this will not work with multiple controllers, nor will it work using Elimination Chamber/Battle Royal & manually eliminating every opponent. You have to do it the boring way: 1 on 1. Pinfall or submission.
I have read that KO victories work but I wouldn't risk it, and frankly it's faster to pin with this method rather than using a finisher or KO move.
For match rules, turn off ring out just in case your kicks knock your opponent out of the ring. I'd turn off DQ and KO (your choice on that one) just to be safe.
It could be worse; there could be no sliders.