WSL — How to run command as root?

Turns out there’s another command simply called wsl that lets you run arbitrary commands as arbitrary users:

>wsl -u root -d Ubuntu-18.04 -- echo "I am g$USER"
I am groot

N.B. you need to use separate args (instead of a string) for this one.

-d is optional. You can change the default distro like

wslconfig.exe /l
wslconfig.exe /s Ubuntu-18.04
wslconfig.exe /l

wslconfig /l appears to be equivalent to wsl --list