Wohoo, my paste got famous!
There are three things you can try to do:
1) Remove the lib prefixes from the libraries in ZK folder:
cp libCSteamworks.so CSteamworks.so
cp libsteam_api.so steam_api.so
2) Download Steam for linux, preferrably with proper architecture, find its .so libraries, and paste them next to Zero-K.exe, replacing the autodownloaded ones. Possibly also rename/copy them like in 1).
3)
Defect to the dark side. Caveat: transition of ingame config not guaranteed to happen without manual intervention, replays on site won't work (you'll have to manually download them to run), missions won't work.