No. The iPhone can do this due to the shape of the home button, and the amount of the fingerprint that can be read without movement because of that. The shape of the home button on the S5 works against this as it only reads a thin strip of the print unless you move the digit.
The only possibility I can think would be a hack to reduce the amount of the fingerprint required for a positive ID. And even if that was possible it would by it's very nature reduce the security offered by the fingerprint reader which could cause issues with the Paypal certification.
Perhaps the videos I have seen were overly simplistic and I'm not getting my S5 until Friday so can't speak from experience, but using the thumb to unlock looked a simple procedure to me and easy enough to do one handed.
- Philips Diga, Nokia 6110, Nokia 3210, Nokia 7110, Nokia 8890, Nokia 9110i, Nokia 8310, Ericsson T28i, Nokia 6310, SE T68i, SE T610, Motorola V600, Nokia 6230, Samsung D500, SE K750, Motorola V3, Samsung D600, Nokia N73, HTC Artemis, LG KU990, Nokia N95 8gb, HTC Leo, Samsung Galaxy SII.