[FIXED] Linux VR
UPDATE: Got it working. The only thing I did differently was launching it through Steam's desktop interface, not from SteamVR Home. This seems to solve the issue. So you can disregard the rest of this thread.
I want to play this in VR, but while the game works nearly perfectly on Linux (the green and red buttons at the start lack text) with Wine, the game never detects the headset even if you try launching it through SteamVR. Steam does support VR on Linux (for a year or two) but only with the native Steam for Linux client. While all SteamVR games (except Croteam's) are Windows-only, Valve created a fork of Wine called Proton which allows Windows SteamVR games to work on Linux. In particular, they have whitelisted Beat Saber, DOOM VFR, and Google Earth - there are other games that work just fine, though. You can play non-Steam games with Proton, but besides what's in the next sentence, I don't know what other VR-compatible games aren't on Steam so I haven't been able to test.
Vivecraft, a Minecraft mod, uses OpenVR. And it works on Linux. That's Java, not Unity, though. Valve open sourced one of their recent demos, which uses Unity, so that may be interesting to look at... but I don't know if anyone's tried building it for Linux, and Knuckles (now Index Controllers) aren't even out yet.
Some other useful links:
https://github.com/ValveSoftware/openvr (some versions of Unity come with an older version of OpenVR that doesn't work with Linux fyi)
https://github.com/ChristophHaag/soundstagevr - Google open sourced Soundstage VR, and this guy made it work on Linux
Looking into this a bit more later.