Mwm: an X11 window manager in 20 lines of code
Is KDE too much for you? GNOME tries to do too much? Xfce still a bit too fancy? Do you need something smaller? Even more minimalist? What about a mere 20 lines of code which provide the absolute barest possible minimum of window management functionality?
You need mwm.
This is the smallest, actually usable window manager I know about. Even TinyWM is twice as large. However, it doesn't let you launch programs, or assign key bindings.mwmdoes.
Mwm's GitHub page
It will open a window, and let you switch between windows, that are always fullscreen. No titlebars, no virtual desktops, no menus, no nothing. This is the true minimalist's experience.