Hide right-hand-side menu from dashboard for students

[pranashreepatil]

Hi I was wondering if it's possible to remove the menu on the right-hand side of dashboard for students/ admin as we want (see image1 attached ). 
Also, can you please tell me can we remove only a section of the menu (see image 2 attached)

Does anyone know of a way to remove it? 

Thanks
to remove menu for studentto remove only start a new course