I think you're looking at this the wrong way. Have you considered why she is so sensitive to criticism, and why she doesn't like it when you ignore her or don't talk to her? She loves you, she admires you. You're the older sibling, she wants to aspire to be as you are. She doesn't like being criticized by you because she doesn't want to disappoint. She just loves you a bit too much, and isn't good at expressing it. Try to talk to her about it, tell her that you love her and that you think she's a cool kid. When she acts well and doesn't have temper tantrums compliment her on how well she behaves, and she'll want to do that more since you told her it was good. Try positive reinforcement, slapping her is just going to make her feel worse about herself. And also, don't think of her as just an annoying little bitch who wants to make your life hell, because she actually just wants to please you.