Can you teach her to clap her hands instead? This could become her sign to let you know that she is frustrated or angry.

I like the idea of teaching deep breaths too. All you can do is model calmness and give her a safe space to calm down in. Have you tried acknowledging her feelings verbally? DS is older than your DD, but he usually reacts quite well to having his feelings validated verbally and he is now, at the age of just over 2 verbally identifying the basic feelings (happy, sad, angry, upset) in himself and others.