0: Normal. The skin will stay visible when showing the desktop and will be brought to the foreground on click.
My question is how can I configure the "brought to the foreground on click" part? By default, the skin is below the current window but how can I configure it such that a click will bring it above the window without minimizing the window or viewing the desktop? Moreover, can this click be changed to a keyboard shortcut or not?
This mode just means that, if part of the skin is visible behind another window, and you click on the skin, it will come to the foreground just like any other window would. There's nothing special about it.