Open hand strikes in Martial Arts?

palm striking the ears is very effective. open hand strikes are used in closer range than fists, so you have to be kinda close to him to use.

I teach fists to beginners. It simply protects the fingers better. When you are advanced then the hands are always open. Open hands are faster. Even in a punch you make the tight fist just before impact but it travels loose.
There are hundreds of Kung Fu styles but Shaolin Kung Fu has lots of open hand techniques. Watch their forms. It's the forms where you can find the definition of a fight. The fights themselves are very much standardized to fit the rules of tournaments.
Great question BTW.

@D Not really, I use open hands regardless if you are close or far away. My hands only are tight when I need to use my fist to hit you with.