You can use skins in LimeWire under Linux almost the same way as you would under Windows.

1. Click on View->Apply Skins -> Get More Skins.
2. When the browser window opens, select the theme that you want to use and right click on the link that says "Download into LimeWire".
3. If you are using Mozilla, click on "copy link location". There should be a similar option in other browsers too.
4. Switch back to LimeWire. It will ask you if you want to download the theme - click yes.
5. Once the theme downloads, LimeWire will ask you whether you want to use the new theme - click yes and enjoy :-)