Kindergarten is a time for children to learn how to handle the school environment. They have to master such things as raising their hands to ask questions, staying with a task until it is done, listening to the teacher, following directions, and behaving appropriately. And, of course, the children should begin learning how to curb their impulses to socialize at any time.
Some kindergarten teachers devote way too much time to pencil-and-paper activities, making it very difficult for young children to remain in their seats and concentrate. This certainly could be part of the problem your daughter is having. Unfortunately, the teacher is not likely to change her approach. Why don't you and your daughter brainstorm ideas for ways she could avoid socializing at the start of the class? Could she simply get out her crayons and color or look at a book when her work is done?
Once you and your daughter have some ideas about how she could curb her tendency to socialize at the beginning of class, the two of you should run them by her teacher. Then, the teacher will know the child is trying to limit her socialization and may even come up with some other ideas.
It will take awhile to modify your child's behavior. After she is handling the start of the class better, follow the same technique in helping her curb her tendency to socialize in other classroom situations. Hopefully, there is some time when it is appropriate for her to socialize with her classmates. Both you and the teacher should always let your daughter know how proud you are of the way she is learning to behave in class.