To Delete a Test Case, click on the icon from the Test Case Overview.

Clicking the Icon will display a pop-up to confirm whether to permanently delete the Test Case. The following prompt will be shown.

After confirmation the project is permanently deleted from the AppTester.
Warning: deleting a Test Case will permanently remove the Test Case and all linked Test Scripts from AppTester. Before executing the deletion be sure the Test Case is no longer used. A deleted Test Case cannot be restored.