You can retarget site visitors with Performance TV Campaigns the same way you do with your retargeting campaigns.
In the Television tab, when you create a new TV campaign, you'll be asked to choose between a Retargeting (1st Party) or Prospecting (3rd Party) audience. Choose "Retargeting (1st Party)" . . .
You can select them from the list on the next screen and click Apply Audience or select Create New Audience if you want to build a new one . . .