Spicy Miso Udon Noodle Soup

Name: Spicy Miso Udon Noodle Soup
Ingredients: 12 oz Baby bok choy, halved (sub regular bok choy, chopped); 1 Tbsp Oil, cooking; 1 tsp Oil, toasted sesame; 1 tsp Ginger, fresh (opt), grated; 2 cloves Garlic, chopped; 1 Tbsp Soy sauce, low-sodium; 2 Tbsp Mirin (sub rice vinegar but reduce amount by half); 1 Tbsp Miso, any type; 1/2 tsp Red pepper flakes (opt); 6 oz Udon noodles, dried; 1 Limes, wedges; 2 stalks Green onions, chopped, green and white parts separate; 12 oz Pork, ground; 5 cups Stock, any type; 1 tsp Sesame seeds, white or black (opt)