Closed is a basic approximation of Emacs's ido-mode for opening files and directories. It'll pop open a panel similar to the command palette and will give you possible completions as you type paths. It'll also expand ~ for you.
Opening Closed
cmd-ctrl-p
(alt-ctrl-p
on Linux): Open a file.
While In Closed
enter
(ortab
): If the current selection is a file then open it otherwise complete the current path.cmd-enter
(ctrl-enter
on Linux): Open current path. If it's an existing directory, open in a new atom window, otherwise create a file.