But I don't want to right-click -- adding bloat to the chrome is entirely the wrong way to go about doing this, but unfortunately Mozilla has a bug up their ass

But I don't want to right-click -- adding bloat to the chrome is entirely the wrong way to go about doing this, but unfortunately Mozilla has a bug up their ass and won't let you do it right as an extension. The right way is to register application/pdf in the browser -- which you can only really do with a native-compiled NPAPI plugin. It looks like it is possible to package them inside a extension xpi, but I'm not sure if addons.mozilla.org will distribute such things.