Not sure what you mean by "opening a repo on a remote server", but if you mean mounting a remote file system, this isn't really a sublime-specific feature. Use SSHFS (or other) and then just open the folder in Sublime and have at it.

If you mean interacting with git directly with Sublime, there's a number of plugins https://packagecontrol.io/packages/GitSavvy. But this does like any normal workflow does -- it creates a local repo and uses standard git commands to sync (push/pull).