1.Click in the Friends feature in the bottom of the screen;
2. Once inside, you need to click in the Pencil button located in the top right side of the screen;
3. After clicking in the Pencil button, you will have the option to "Remove" your friends. Press "Remove" in order to complete your task.
If you wish to delete Facebook friends:
- You need to delete them from your Facebook account
- Log out from your game and log in again