Yes you can.
You can delete some Users at the same time by using CVS file.
(However, you can't delete Users who are authorized to be manager.
If you want to delete authorized User, you can do it from "delete" button on User List page.
Please refer the way below.
1. Go User list page from "User Management", and select "Export" button. You can get User information in the form of CSV file.
2. Open the exported CVS file. Leave bulk users only that you want to delete (You have to delete users that you don't want to delete). And save the CVS file.
3. Select "User Bulk Delete" button on User List page.
4. Select the CVS file saved by procedure 2 on the User Bulk Delete page.
5. Select "Delete Preview".
6. The target Users that you want to delete will be shown. Please make sure if there's no mistake.
* Once you delete User, its study history will never been taken over even if you recreate it with the same information.
7. After you checked, scroll the page till the end and push "Delete" button.
8. You will back to User list page after push the "Delete" button.
If the confirmation of the delete is shown above of the page, it is correctly done.