Probably not a good idea to put a click event inside a click event. I'm not familiar with this mask plugin, but speaking in the abstract, you can clean it up by doing something like this:
$('.open').click(function() {
$('#workspace_menu').show();
});
$('.tutorial, .next').click(function() {
$('.mask').hide();
$('.action_list').show();
});
Make sure you separate multiple selectors with a comma in the case of .tutorial
and .next