If you are referring to the table with tabs, that appears to be imported from 3rd party content and likely is not something that can be forced to show full screen. The size of the table is likely controlled by the 3rd party's code. However, if you are referring to the entire area in black, there might be a way to make it larger, but not full screen (unless it has an option for full screen viewing). At the top of the course menu (that says Home at the top), there is a three line button above Home. If you click on that, it will retract the course menu and expand the content. It does not remove the Site navigation on the far left (Dashboard, Courses, etc), but maybe this will help.
