(W10) Register application to manage phone numbers in web browsers (like skype)

I need to register my app coded in c# on (at least) Windows10, in order to make it elegible to open URLs that are phone numbers on web browsers (preferably Chrome). If i'm not wrong, skype does/did it. Anyone knows how to do it?

Best regards and thanks in advance :)

UPDATE: Thanks to Oscar for his answer.

I've tried to put this keys:

HKEY_CLASSES_ROOT
   tel
      (Default) = "URL:tel Protocol"
      URL Protocol = ""
      DefaultIcon
         (Default) = "c:\Program Files\Test\Test.exe,1"
      shell
         open
            command
               (Default) = "C:\Program Files\Test\Test.exe" "%1"

When I click a phone number with this scheme ("tel:nnnnnnnnn"), both Chrome and IE open a new windown allowing me to choose what app open, but my custom app doesn't appear :(

UPDATE 2: Seems like is not possible to do it on W10 (see comments bellow)

Solution

Seems like is not possible on W10...

The way that the applications can set itself as default ones has changed. Now the user is who decides what app should do the action... and the app has to be on the Windows Store...

See this article for a full explanation:

http://www.tenforums.com/software-apps/21303-how-do-you-set-protocol-association-standalone-exe.html