How do I remap escape when in Sublime Text vintage mode?

Also, Ctrl+[ works and is much easier to reach for than the esc key. This is in OSX at least.

"Vintage mode is implemented entirely via key bindings and the plugin API - feel free to browse through the Vintage package and see how it's put together. As an example, if you'd like to bind "jj" to exit insert mode, you can add this key binding:"

{ "keys": ["j", "j"], "command": "exit_insert_mode",
    "context":
    [
        { "key": "setting.command_mode", "operand": false },
        { "key": "setting.is_widget", "operand": false }
    ]
}

Just modify first line to jk if you prefer that.
Source

If you are using the Vintageous plugin, use the following key binding:

{
    "keys": ["j", "k"],
    "command": "_enter_normal_mode",
    "args": {"mode": "mode_insert"},
    "context": [{"key": "vi_insert_mode_aware"}]
}