I wonder if this could be used to boost resolution of SEM and similar devices with electrons instead of photons. It'd make imaging non-metallic objects a lot easier since you won't have to bombard it with as many electrons, potentially destroying the object you want to examine.
Unlikely. Resolution limits are determined by aperture and wavelength, which is unrelated to photon number. There may be other tricks that can get around those limits, but they will be quite different from this sort of photon-number stuff. Photon number is conjugate to phase, whereas to improve resolution you need to know phase very precisely, so the uncertainty in (and therefore the number of) photons goes up.
"Photon number is conjugate to phase' - I'd like to understand that better, is it the same as saying photon counting destroys phase information? Would it also hold true for gated counting?