To disperse powder consider using a devise used by artists which is 2 small diameter pipes at about right angles. Immersing one in the powder and blowing into the other creates a "vacuum" lifting the paint up the former pipe and creating a cloud of paint (in this case powder). This may be to what you are referring. A thin plastic film shroud over the instrument of dispersal and specimen should serve to minimize any mess. I have a plastic belows which I use to blow out my keyboard (picked up at a medical surplus) but a length of surgical tubing may make the process easier.

Another consideration is the refractive index of the mounting medium. For decades the use of Canada Balsam was used for mounting rock specimens. Using Epoxy glue is certainly feasible (don't recommend using 1 minute epoxy). For slap dash perhaps use of nail polish will do. These are all about 1.5 ri if memory serves me well.

Depending on how well the powder is sorted (presume to be quite fine) you may wish to first pass it through a set of fine sieves. Example, geologic grab samples might use a 0.03 mm sieve then embed the "dust" in epoxy by spreading it on and pushing it down into the epoxy with a cover slip. This way all the material is of a consistent size similar to working with thin sections under crossed polarizing filters. This makes it easy to identify content and even determine rock type, if it was taken from a hand specimen and ground down. I can imagine a similar approach would be used for CSI analysis.