By Frank McGurty and Daniel Trotta LOS ANGELES (Reuters) -Best actor winner Will Smith smacked presenter Chris Rock in the face with an open hand and shouted a vulgarity at the comedian for making a joke about his wife Jada Pinkett Smith’s hairstyle in an epic moment overshadowing the Oscars ceremony on Sunday. Minutes later, when accepting his first Oscar for best actor for his role in “King Richard,” Smith apologized to the Academy of Motion Picture Arts and Sciences and his fellow nominees in a tear-filled acceptance speech, but not to Rock. “I want to be a vessel for love,” Smith said, wit…