Disclaimer: this is purposefully obtuse.
Other effects in the game which explicitly state they kill you:
Shadows, succubi, massive damage, death saving throws, beholder death ray (notably not even their disintegration ray kills you), power word kill, vampires, mind flayers, night hags, drow inquisitors.
Clearly, if they intended for disintegration to kill you, they'd have said so. Since specific overrides general, and there is no general rule that disintegrated creatures are dead, I rest my case. QED.
Get the feeling it would be difficult to have a dust based strength character though. Hard to hold weapons/make attacks with them as dust.
Maybe wizard?
"As you cross the street you take 1d4 of wind damage. Please make death saves."
"it starts misting as you are traveling"
Roll to not get washed away
Due to the failed Dex save you have been dissolved. Please make Con saves for drowning.
Two-handed weapons require two hands, and one-handed weapons require a free hand to load. But you could use a one-handed weapon that you don't have to load. Or rather, you don't even need to do that, since no weapons are listed as being one-handed.
Just have someone carry you around in their pockets, then throw you in the enemies eyes to temporarily blind them.
Blind possibly but would you get weaker the more dust lost?
Still needs an arcane focus and the spell components could be problematic. Monk maybe? (A dextrous pile of dust gently (yet masterfully!) being blown at enemies)