The tag below your question says that you are using TurboTax Online. But in TurboTax Online you wouldn't have multiple returns or a "front page where you select a return to work on." So I assume you are actually using the CD/Download software.
If you are in Windows, on the "front page where you select a return to work on," click on the return you want to delete. It will then be outlined with a blue border. Press the Delete key on your keyboard. Select the option you want, and click OK.
I believe it works similarly on a Mac.
