Student or Learner
1) I think we should see the teacher because she wants to tell us what she thinks about our performance for this semester.
2) The coach will tell us about her evaluation/assessment on our performance and give us constructive criticism.
should be "our performances" because it refers to more than performance (our performances), and "during this semester"
I would say "evaluation / assessment of our performances"
Pluralizing the word "performance" makes it clear that she is viewing them as separate. Since "us" indicates there are more than one person involved, "performance" should be plural. If instead it is actually a group (like a group doing a skit), then "us" (and "we") should be changed to something like "our group."