A small (not-so-)technical answer
«Just how does one see (as opposed to "see" and ""see"") things with "synchrotron X-ray holotomography"?»
Erm. By looking at the attached monitor. Word of the street is, results are improved if you keep your eyes open.
A bit like, you know, how you see things with an electron microscope, an echograph or any piece of medical imagery equipement, a scanning confocal microscope, a giant telescope, ...