Ofcourse, it starts with a recent OS (windows, linux, mac) on which you install VLC.
After installing, do not change any setting, some interfere with remote control!
Then follow these points:

set up the beamer and detect it as a second screen.
go to your display settings, and first of all set the background of everything to black.
next, make sure the display is extended, not copied, to the beamer and do not extend the statusbar or anything else to the beamer 'screen' (in windows, scroll down and deselect 'set taskbar on all screens'
take note of the screen resulotion of the primary screen
create a startup file (.sh in linux/mac or a .bat in windows) and edit this

for windows, enter:

VLCstart.bat

start "" "C:\Program Files\VideoLAN\VLC\vlc.exe" --extraintf http^
 --video-x=2000 --video-y=50 --fullscreen^
 --no-video-title-show --no-embedded-video --http-password=yourpassword^
 --http-src="c:\Program Files\VideoLAN\VLC\lua\http"

(make sure to add the spaces before the new lines after ^)

change --video-x to at least the witdh of the primary screen (in pixels) plus 1 (so for instance 1281 instead of 1280)
Save the file
make sure that when nothing is playing or running, that the beamer 'screen' is entirely black, no icons, no taskbar, nothing.

Now, only start the player using that startup file, it will then play the file on the secondary monitor. The reason that happens is that the player is instructed to play the file on 1 pixel to the right of the primary monitor, and make it fullscreen.
The reason for this trick: on some systems, the screen option simply does not work.
If vlc is not playing on the correct screen, then move the desired screen to the right of the primary screen in the video/monitor setup or set the video-x and video-y to the correct (negative or positive) coordinates to get at least half of the video playing on that screen. If switched to fullscreen, it will then be on that screen.
You do still get the VLC GUI on the primary screen, so you can add your movies on the playlist there.

Once running, it is easy to control VLC using it's http interface.
For this you can open up any browser, and enter the URL: http://localhost:8080 or use the ip address instead of localhost when you want to control it over the network.
The page will then ask for a username and a password, which is no name and the password you set in the option --http-password
Just going to that address shows the vlc interface but if you add /requests you get to do more!

for instance, get /requests/README.txt will show you a complete command list.
/requests/status.json will show you the state of the player in json. use .xml to get it in xml.
/requests/playlist.json to gather what is stored in the playlist (most importantly, the medialibrary, usually id 2 in the children list).

Knowing this, it is easy to come up with some controller that will do calls to the VLC http interface and make it do anything you want.