I don't want to mirror my monitors but I would like the files in ~/Desktop to display on both. Right now they only display on my primary monitor. Is it possible?
You can't make items appear twice on what is essentially the same desktop, but you can view the contents of your desktop as a folder.
The simplest method using default settings is to open a new folder in Finder, Cmd ⌘ N , then Desktop should be one of the Favourites on the Sidebar.