Alt+D and New Tab

rajarammenon

Alt+D does not work
Right click on a link for opening the link in a new tab: From 'current' page, Vivaldi takes you to the new tab which is very unlike other browsers. There is no need to immly switch to new tab. It is better to continue with the 'current' page.

A Former User

The next option in context menu is Open in background tab. That's what you're looking for. You can also use Ctrl+click or a mouse gesture (set it in Settings → Mouse)

npro

cc: @Gwen-Dragon Alt+D must be a shortcut for focusing the address bar in some browsers, in Vivaldi it's F8 or Ctrl+L or you can assign your shortcut to it in the keyboard settings vivaldi://settings/keyboard/ (For example I have assigned Ctrl+K for the address bar, Ctrl+L for the search bar)
If you mean opening the link in a tab in the background potmeklecbohdan's advice applies, additionally also middle-click on the link.

Pesala

The feature request to Add Alt+D as a Default Hotkey for Focus Address Field only has a few votes, but it would be very easy to implement.

You can easily add it yourself in Settings, Keyboard, Page, Focus Address Field.