Step 1) To Delete Accounts in RedditDominator you need to browse: Account--> Accounts Manager
On this screen you will find 5 buttons like : Add Single Account, Load Multi-Accounts, Select, Update and Delete.
Step 2) Click on "Delete Accounts"
To Delete Accounts you need to click on button "Delete". Once clicked a modal window will Popup and either you can select "Delete selected" or "Delete Non Working" or "Delete All" option as per your choice.
Getting trouble in deleting accounts contact support.