Soba noodles are a Japanese noodle made with buckwheat flour; if your supermarket doesn't have them in the international foods aisle, try an Asian market. This is not a strictly authentic yakisoba, but it's awfully good!
In a large skillet combine sesame oil, canola oil and tonkatsu or hoisin sauce. Stir fry 30 seconds. Add garlic and ginger and stir fry an additional 30 seconds. Add chicken and soy sauce and stir fry until chicken is no longer pink. Remove mixture from pan, set aside and keep warm.
In the emptied pan combine the onion, cabbage, carrots and bean sprouts. Stir fry until cabbage begins to wilt. Stir in the cooked noodles and the chicken mixture, and serve.