Yep. That's what the official server is, really. Just hedgewars-server running in a tmux/screen session.

https://hedgewars.org/node/6902

I followed the instructions there and started it like this:
hedgewars -d true

But it still opens the full game window... How do I make a dedicated server?

The server is a different program and is called hedgewars-server, not hedgewars.

Great! I see I set it up on another host properly. Where do I get a list of active servers?

There's an unofficial, manually created list of known here:
http://wiki.hedgewars.wohlnet.ru/wiki/List_of_servers

But the list is old now. There are currently only a very few people who actually run a Hedgewars server.

If you click on “Play in local network” in the main menu, you might also see a list of servers, but only those in your local network (and even then there's no guarantee Hedgewars will automatically find them all).

You usually have to enter the adress and port manually by clicking “Connect to …”.