The best way is to use "Factory Reset" from the "Troubleshooting" page. It does not work on Windows right now because there RD restarts right away, recreating all the files and directories. But on macOS and Linux doing a "Factory Reset" followed by deleting the app should remove everything.
I think there may be a few omissions, like the
~/.kuberlr
directory, and maybe some Updater stuff when an upgrade has already been downloaded, but otherwise it is pretty thorough