If you select ‘sidebar hidden’ in the page settings then you’ll have the map the full width of the page container.
If you mean full width of the browser window, then not really. The map is inserted as an iframe inside of the main page container, which has a set width of 960px. So at 100% it will never go outside of that container.
You can hack it a bit with css and force it outside of the container, but you could run into issue with the responsive side of things as the browser window resizes. You can try it out and see how it works for you using the css below, simply copy/paste into your style.css and save.