1. Cook noodles as package directs. Drain and divide among 4 bowls. Meanwhile, combine soy sauce, sesame oil, and broth and set aside.
2. Cut tofu lengthwise into 3 pieces. Cut crosswise into 1/2-in. sticks and blot dry. Heat 1 tbsp. vegetable oil in a large frying pan over high heat. Brown tofu (don't stir), 4 minutes; brown on other side. Set on noodles.
3. Add remaining 1 tbsp. vegetable oil to same pan over medium-high heat. Cook ginger and garlic until fragrant, 30 seconds. Add bok choy and cook until wilted, 5 minutes. Add reserved broth mixture and cook until hot, about 1 minute. Spoon mixture over noodles and tofu and sprinkle with onions.
Note: Nutritional analysis is per serving.