Hand of a thousand Bells is a technique that focuses a burst of displaced air combined with a bit of the body's own energy (chi, ki, etc.). Simplest demonstration is setting up a candle, focusing your energy into your hands and forcing it outward with the air that you displace by pushing towards the candle. Do be careful.
Until recently, I never had a name of it until I came across some kung fu teachings. It is a technique some of us have been working for years, including myself. Air is certainly not my best element but you should still try to have a well rounded balance of your elements. My two best are Fire and water; yes they are antithetical and that in and of itself is kind of a long story. Most of you know it already though. I have however had quite a bit of success with this technique. My best experience though was when I was in the military and someone attempted to splash a bottle of water at me and I reflexively did the technique and all the water went flying back at the people. Didn't get a drop on me. So yes, it does work quite well and my affinity for water showed through. Enjoy.