Is he like this at home? (I mean, obviously his personality is his personality, but are you able to control him?) If you're able to keep him under control at home, then there's no reason they can't keep him under control at school.
I have some experience here, because my youngest was a real challenge at that age. She has all the personality in the world, and will run all over anyone who allows it to happen. She was quite the firecracker in preschool. The teacher would complain to me constantly about how out-of-control my child was, and finally what I did was call a meeting between the teacher, the director, and me. What I told them was this:
1) I know what my kid is like, and I understand she is a handful.
2) We are able to keep her under control at home using these methods: (and then listed the methods my child responds well to)
3) Please do not complain to me about my child's misbehavior at school - it is without a doubt the teacher's responsibility to discipline my child while she is at school. I send my child to school well rested, clothed, and properly fed so she is able to meet the challenges of her day. Once I drop her off, I can't be expected to magically discipline my child from afar. The teacher needs to take responsibility for this.
4) If there are persistent issues that are not corrected by consistent and firm discipline at school, rest assured I will back up the teacher and will enforce whatever means necessary with my child at home to ensure her willing compliance with her teacher at school.
After that meeting, I went home and told my daughter this:
1) You will listen to your teacher, and you will do as she says.
2) If you choose not to listen to your teacher and I hear about it, you will go to bed 1 hour early for each infraction. A child who is unable to pay attention and behave must be tired, and must need more sleep.
But honestly, once the teacher was clear that I'm a huge proponent of discipline, that my child does not misbehave at home, and that I considered it the teacher's responsibility to make discipline consistent at school, there were ZERO problems.
Once in Kindergarten, my daughter came home with a "blue card," meaning she'd been disciplined at school. She was sent to bed an hour early that night, and we haven't had a problem since. (She's now in 2nd grade.)
Good luck!