Final sale or Auth only for refunds

Hey guys,
I am using paypal express checkout, and in the admin page >> payments i chose the default in Payment Action:
How do you want to obtain payment?
Default: Final Sale or Auth Only

which one is better? and which one can i use to cancel the order from the admin site instead of going to paypal? i had a test product to use for testing if paypal works and it did, but for refund, the only option i saw was to delete the order, which i think will only delete it from the admin page but not void it and issue a refund?

Tnx guys
Joe

Finance is done where it is processed, PayPal or otherwise

Oh i see, so you can only void the transaction through paypal but not from the store admin page,
Tnx kobra
Joe