Instantly Open Anything with Quick Look in OS X Using a Simple Tap Gesture
Did you know you can instantly open any file into Quick Look with just a simple gesture? From the Finder in OS X Mountain Lion onward, all you need to do is hover the cursor over the file in question, then do a three-fingered single tap on the file to immediately launch the document into Quick Look’s Finder preview. This tap gesture even works to launch Quick Look from the Open and Save dialogs, just like the traditional spacebar command.
If you want to go further than Quick Look, once the file is previewed just right-click on the “Open With” menu to launch the file into any compatible app.
Somehow this new little gesture completely escaped me, so heads up to MacGasm for the simple yet useful tip.