As of now as a TA, if I want to cycle through all the students' turned in assignments, I have to:

1) go to People
2) choose the first student
3) choose Grades from the pop-out
4) choose the Assignment.

I should be able to access their turned in assignments from Grades, People, Assignments, etc.

In general, I think Canvas' flow isn't super well thought out. Features are tucked away in un-intuitive spots (such as the students' turned in assignments).