full frame cameras mean big lenses?

I was reading something recently regarding CCD sensor and CMOS sensor differing with how they gather light when the sensor is hit by photons at a perpendicular angle. As I understand it (very foggy), CMOS sensors can't render the light well if not hit at a certain angle, but CCD can? I read this under the context of large lenses don't necessarily mean large bodies; i.e. Leica M9 has small lenses (relatively), but also sports a CCD. The reason I ask is because I would very much like to see an affordable full frame mirror less camera with relatively compact lenses, and Canon hasn't thrown a punch in the mirror less ring yet. I doubt it will happen, but would making a relatively compact mirror less option require a different kind of sensor? Or, why is their the association, or myth, that larger cameras require larger lenses? Thanks.