A few extra tips to people trying this:

1. Start with Gala or Honeycrisp apples, they are the easiest to do, so you can learn the technique. Granny smith and other green apples are damn near impossible when you start out.

2. if the two palms together thing does not work for you, try one palm, and one thumb down in the stem, sometimes thats easier.

3. 'find the sweet spot' I always start out by putting a thumb in the stem, and sort of rotating the apple and feeling it, after a little practice, you sort of develop a feel for finding the direction to try and split the apple. They are all different, but there is generally a 'sweet spot' which the apple breaks along easier than other angles.

4. remember, your basicly pulling it in half, don't squeeze to much, but rather, think of it like opening a book that is stuck shut, with the spine at the base of the apple and the pages at the top, where your palms are.