It is courageous of you to want to ask forgiveness from your teacher. When we seek forgiveness, please remember the “3 R’s” of remorse, repentance, and recompense. Remorse is the inner sorrow for what you did. Repentance is knowing you did wrong and wanting to make it right. Recompense is what you do now in a behavioral sense to make it as right as you can. When you write the letter, please keep the 3R’s in mind. They may help you craft a focused and sincere letter. By the way, the letter itself is probably the recompense in this case.
Regarding finding the teacher, is she still working? If so, send your letter to her at the school. Is she retired? If so, send the letter sealed in an envelope addressed to the principal. Ask the principal (in a separate letter addressed to him or her) to forward your letter to the teacher. Please be sure the letter to the teacher is in its own sealed envelope for the sake of privacy. You can always follow up with the principal to be sure your letter was forwarded to the teacher.
Finally, the teacher’s strong reaction may have been an injustice to you. If you think that is the case, then please work on forgiving her for the strong reaction. Feeling like you were going to be choked may be sufficient grounds for your forgiving her.
Thank you for having the courage to do all of this.