Currently the fastest way to flip the normals of a single surface is “W” + menu selection of Flip Normals, correct?
I’d like to be able to simply press a hot key to achieve this, but I didnt notice the Flip Normals menu setting in the User Preferences=>Input settings box. Any idea how I can set this up? 
You will need to add a new keymap item to it.
Go to User Prefs>Input>3Dview>Mesh>Add New (This will be at the bottom of the list).
The python operator can be found by hovering over the original button in the tools panel.
Check the other shortcuts of the same category to check how to wrote the operator, often only a part has to be given.
Question to other people: How do you find the python operator name for something without a button, like splash screen?
Hovering on search bar doesn’t show it.
Worked like a charm. Thanks! 