One of the things that trips me up with VS Code is my muscle memory for switching tabs with ⌘ + number. I used this often with Atom and I am pretty sure I picked it from Sublime and/or Textmate.
Digging through the existing bindings, you can do this today with ⌃ + number. What makes this worse for me, ⌘ + 1, ⌘ + 2, etc do something today, but I am honestly not sure what it is. :)
There is an Atom commands plugin, but I do not need (or want) everything that comes with it. Instead, I went ahead and edited the following keybindings (under workbench.action.openEditorAtIndex).