Can comments be hidden on the Employee Evaluation Summary report?

This feature is available on the Premier and Master payroll edition.
Yes. To hide the evaluation comments on the Employee Evaluation Summary report, enable the "Hide Comments on Summary Report:" tick on the Evaluation Processes screen.
Configuration > Human Resources > Performance Management > Evaluation Processes


A report that reflects both reviewers’ ratings is obtainable from the employee’s Evaluation History Screen. Selecting the above option will hide the comments recorded during the review.