Sentence:  And there were other words that stung his ears like hail: 'Slut! Bitch! Whore!' each accompanied by a noise: the <WSD>open-handed</WSD> slap that sounded like the tearing ofcalico, the dull thud followed by a gasp as a bunched fist slammed into yielding flesh, the reedy shriek and the gurgling sob -- and eventually the whistling breaths as Jessie climbed the stairs and shouted until she made herself heard that if they didn't stop their racket right this minute then she'd be calling the bobbies. 
Meaning of the word marked with <WSD> tags:  Done with the hand open rather than clenched