How to identify high risk users, rules, applications or websites?

Select BI Reports > Behavior Alerts then click the Risk tab: 

You will see Top Risky Employees, Top Risky Departments, Top Risky Rules etc. You can also create your own custom report and add any rated items you want. For example, Top Risky Object, Top Risky Object Type etc.

For more information, check out the BI Reports section on the User Guide.