Make users into moderators to help you engage and manage the community. They can delete and hide posts, as well as managed posts, comments, and messages that have been flagged by other users as problematic.
First you'll want to find your user in the User Directory (located in the Admin Menu).
Once you've found the user you want to promote, you can change their role in the far right column.
Once a user has been made into a moderator, they will have access to the Oversight section of the Admin dashboard.