C.S.
Tantrums at that age are usually a symptom of something else and since kids at that age don't yet have the coping skills or the ability to fully express themselves in words it has to come out some how.
I would trying showing her empathy rather then punishing her. In a calm moment, (like snuggle time before bed), ask her why she is having a hard time at school....she may still not be able to tell you, but if she starts to realize she can come to you instead of being scared of getting in trouble it might lessen the tantrums.
She may also just be scared/nervous/missing you, etc.... letting her know you realize that will help immensely.
When you drop her off in the morning set the expectations that she be a good listener, etc... and then when she accomplishes it and you learn about it at the end of the day praise her like crazy...and when she has a less then stellar day let her know there are consequences for that...like not watching her favorite show that night. It will take her awhile to adjust, but eventually they catch on to the cause and effect. You have to be consistent though.