As soon as I can submit this pull request, Dave can add this capability into the dashboard sidebar -- but that will take a few days.
If you can't wait for that new feature, then you may be able to brute force it by adding a ui_template
node with a script that finds the Navigation Menu and hides it -- something like this:
<script>
$("md-sidenav").hide();
$("md-toolbar button").hide();
</script>
TBH, this will only keep the Nav menu from being shown, so I'm not sure what other side effects will happen.