Recently I went to a Maps and Atlases/Rx Bandits concert ( It doesn't matter if you don't know who they are ) One of the guitar players had a tendency to play on the strings past his bridge. This is usually only possible on guitars with floating bridges I believe ( ie: Hollow-bodies) To further explain they are the strings that sound very similar to the strings that are at the head of the guitar, they are under a lot of tension and have a very high shrill sound. I was wondering what that area of the guitar is called past the bridge and also if there is anywhere I can go to look up techniques to come up with interesting sounds with these.
Any input would be helpful. Sorry it's wordy

TLDR: What are the strings past the bridge called, where can I go to learn how to use them successfully.
Trial and error? I don't think there's a specific name for that technique. You can do it on any guitar with a TOM-bridge if I'm right.