Most of the actions I typically use in Picard have keyboard shortcuts, except for "Remove" which means moving the mouse pointer up to the button on the toolbar, and clicking... which means taking my hand off the keyboard which I've been using for the previous several actions.

It seems like just adding something like:

self.remove_action.setShortcut(QtGui.QKeySequence(_("Ctrl+J")))

to picard/ui/mainwindow.py would be sufficient. (If not ^J, some other appropriate key combination.)