So I made miso powder, and it rehydrates fairly well. You can also put it in a container with a shaker and shake it on food, where it hits it like a salty umami bomb. Technique here: https://billievethat.wordpress.com/2009/11/23/miso-dust/
The main mistake I made: I didn't spread it quite thin enough. Because of that I had to dry it for a really long time. Towards the end I got impatient and upped the temperature; it ended up giving it a "toasty" flavor which is also interesting but would be nice to try again without that.