I was with my friend Suzi a week or so ago and we were making raw chocolate mousse. The base is avocado. Suzi dig her fingernails into the avocado skin and RIPPED it open with her hands. I laughed almost too hard to take the second avocado away and cut it properly. Then it occurred to me that other people might do this ripping open thing. I wish I had a picture to show you the mangled green mush when she was done. So, just in case you need it, here is an avocado tutorial. Oh, and I didn't make this up. I saw it on the Food Network. And some of the pics are taken by a five-year-old so they're horrible.
Here is the knife I use. It's called a santuko knife. A sharp knife is ALWAYS better than a dull one.
Pick a place and cut all the way through to the pit (stone). TURN the avocado so you cut ALL around the entire thing.
TWIST and it will come apart.
Take the half with the pit and hold it firmly.
Slam the knife into the pit - DO NOT wind up like you're pitching a fastball first. Just raise the knife several inches and smack it into the pit. Hard.
Twist again and the pit will come out.
I use the same knife and lightly score the avocado - here I diced it, but you can just slice it if you want.
I like to eat it with cheesy scrambled eggs and tomatoes.