I've seen several usability guideline documents for mobile devices before, but unfortunately not for games specifically, which are a different beast entirely.
For your example, I guess that would have to vary from game to game. If for instance your game used double tapping or sliding as part of the gameplay mechanics, then obviously you would no longer be able to use that motion for pausing, so a standard wouldn't do you much good.
I've just checked a dozen of games on my library, and most of them display a little pause button (or just the symbol) on one of the corners of the screen to bring up the menu, so if anything, I'd call that the "default standard".
My advice is simple - play a bunch of games on your target platform and see how they are usually done. Assume the majority as being the standard and see if that implementation would also fit your game. If it doesn't, just find your own alternative! And don't be afraid to think outside the box, if it works well.
For instance, I used to see lots of action/RPG games with d-pads drawn on the screen and thought that was the obvious solution... Then I played Final Fantasy III on the iOS and there's no d-pad drawn anywhere! You simply hold your finger down anywhere on the screen and as soon as you move it a little, that place becomes your d-pad (and a little d-pad graphic appears beneath your finger). This means I can play holding my device in any way I like and with either hand. And to perform actions such as talking with NPCs, a single tap anywhere does the trick. I found this pretty amazing, that you're able to completely control an RPG of moderate complexity, with a single thumb.