Is it possible to assign a specific command to a tool in minecraft, e.g. A stick that automatically spawns a flash with a right click? Like the private game tools on gomme. How does that work?
It depends on where you want it to be.
For a Spigot / Bukkit server there's this plugin, which binds the commands to the tool: https://dev.bukkit.org/.../powertool
However, then either a tool that inserts the Blitz Command would have to be added, or just a look at how to use the standard commands.
For a single player world, unfortunately, there would be no mod in my head that does the same.