Bring a pot of salted water to a boil. Add the tomatoes and cook for 3 minutes. Let cool. Peel and add to a blender. Process the tomatoes, peanuts, peanut butter, and adobo sauce until smooth. Season with salt and freshly ground black pepper, to taste.
Add the sauce to a medium skillet and add the chicken. Stir for 3 minutes over medium heat until warm. Transfer to a platter and sprinkle with sesame seeds and chopped cilantro. Serve with warm tortillas or white rice.