This sets the "Set Print Area" command on Excel to 'Cmd-Shift-Alt-Ctrl-k'
defaults delete com.microsoft.Excel NSUserKeyEquivalents -dict-add "Set Print Area" -string "@$~^k"
It does work, but you get cramps in your fingers.
You can delete all keybindings in an app with
defaults delete com.microsoft.Excel NSUserKeyEquivalents
I can't seem to delete only one keybinding.
Listing keybindings works like this:
defaults read com.microsoft.Excel NSUserKeyEquivalents
which will give you:
{
"Set Print Area" = "@$~^k";
}
and in case you can't find your app
defaults domains|perl -lpe "s/\, /\n/g"
will neatly list all the domains and
defaults find NSUserKeyEquivalents
will list all the user keybindings
Sources: