In the top toolbar on the Canvas Course Reserves tab, there is a Usage Statistics link. Clicking on that link will bring you to a view that ranks all of your course reserves by the number of students have clicked through.
The number of click throughs are listed in the "Usage" column. By clicking the hyperlinked text "Show Detailed Usage" you will see more information, such as how many students have clicked through to the reading and on what date(s).
Unlike other tabs within your Canvas courses, you cannot view Course Reserves from Student View (which you would normally select in the Settings tab). If you want to see the way the reserves page looks to students, you will need to select "Switch to Student Mode" from inside the Course Reserves tab. This option is found on the top right hand side of the page.