.NET Core

.NET Core is fully linux compatible and can be developed using Visual Studio Code. All free! Finally, Micro$soft...

This was a pretty easy method:

Install vs code
Grab an existing project
Open it in vs code
Let vs code install all the support extensions, including C#. You might have to restart code a couple times to get it eventually be happy.
Once it has settled down, check out launch.json. It may ask you to remove it and recreate it, instructions provided in the file.

Not bad!

Everything is eventually done on the command line, here's the reference.