Is there a desktop / web app to manage Android contact linking? Contacts on my Android phone come from different sources (Google account, Facebook, Skype, Windows Live etc.) and I can link them manually using the People app or how it's called. The user interface is not too bad but still, if there was a desktop / web application for this I think I would prefer that. Is there any?

Things I've tried and that don't support this:


Google Contacts (only supports Google account contacts, not Skype, Facebook etc.)
Samsung Kies
Remote Web Desktop
Airdroid
Unfortunately, no, there is no sort of cloud service that will handle this for you.  Since the combination of contacts from the various apps you have installed only exists on your phone, no one of the services you use will be able to make global changes to your contacts.  

This is not to say that it's technically impossible to do what you're asking:  Since it's possible to write an app to make changes to contacts, and since it's possible to write an app that could act as a web server, there's nothing preventing a program from providing a web-interface to the contacts on a phone.