Editors can delete users in the same way as any other content in the system. All content uses the same access rights system. You can delete a node if you are a member of a group that has Edit and Publish Access to the node (user).
If you only are a member of the Edit Access group, but not the Publish Access group, you will be able to request a delete from the members of the group with Publish Access to the node. If don't Edit or Publish Access, you will not be able to edit or delete the user at all.