I'm afraid that this is no longer possible, but I have got the same function with this application http://www.4t-niagara.com/tray.html
Free version will be enough as it has "minimize to the tray" option on the titlebar right click menu. You only need the paid version if you want to set Firefox to always automatically go to the tray when you minimize it.
You can get it to do so with the free version as well, however it will forget that setting when you restart the computer.
Yes there are free applications for this available as well, but when I looked around, they were mostly last updated when windows 8 was new thing (2012/2013). This seemed to be only app that wasn't abandened, and knowing how Microsoft seems to like to fix things that aren't broken. Having updated app would sound like a good idea to me.
Cool, but not practical. There's a addon called 4t Tray Minimizer that I'm using, that has the option to turn windows transparent. If you try it, you'll instantly discover it's very difficult to read transparent windows.
You can use the program, 4 T Tray Minimizer. It lets you minimize windows to tray. DL from here: http://www.4t-niagara.com/tray.html or here: http://download.cnet.com/4t-Tray-Minimizer-Free/3000-2072_4-10079431.html
What I plan on doing when I get an OLED:
1.) Kill Windows Explorer in Task Manager. Technically that's all you need to do to get rid of the taskbar. (Also removes access to your Desktop icons + Start though.) Might be able to configure a script to run on login to do this automatically.
2.) http://executor.dk/ -- in its dark/compact mode -- allows me to bind a shortcut to pull it up like the windows run prompt. Essentially a Start / Run / Search replacement.
3.) http://www.4t-niagara.com/tray.html (free version is good enough) enables minimizing to the taskbar / hot keys/also has a neat transparency feature. Enables hotkeys to hide all open windows to tray (Win + D), restore with Win + Shift + D, minimize individually with Ctrl + Shift + Esc, and enable alt tab functionaliy. You can set it to whatever hotkeys you prefer. If you just minimize a screen with explorer not running it goes into a box in the bottom left on screen, which is why I found this necessary.
Anyway the above combination completely replaces Windows Desktop/Taskbar in the most minimalist form. There might be a better desktop/taskbar replacement, but I haven't found one completely unobtrusive yet.