Drawing> optimize> Remove contour strokes
I love it, I use it all the time to clean up my drawings of unnecessary lines but i cant find it in the list to make a keyboard shortcut for it.
The closes thing i found was Flatten and remove extra strokes which does prettymuch the same but ignores strokes outside the drawing.
It would be also interesting to just right click on any function and get the option to add keyboard shortcut from there instead of going to the prefferences and search for the speciffic function.