Cook the udon noodles according to package directions. Combine the soy sauce, vinegar, hoisin sauce, and 1/4 cup water in a bowl. Heat a large skillet over medium high heat. Add the sesame oil and the chicken. Season with black pepper and brown all over, breaking it up as it cooks, about 5 minutes. Add the bell peppers, ginger, and fresno pepper, and cook another 2-3 minutes. Slowly pour in the soy sauce mixture and basil. Bring the mixture to a simmer and cook until the sauce coats the chicken, about 3-5 minutes. Stir in the noodles and remove from the heat. Add the green onions and sesame seeds. Serve the noodles warm, topped with green onions. Enjoy!