Make the sauce. Whisk together the hoisin sauce, chili garlic sauce, toasted sesame oil, soy sauce, ginger, and garlic until smooth.
Bring a large pot of water to a boil. Add the udon noodles and the edamame and cook for about 4 minutes, or according to package directions, until noodles are tender. In the last 30 seconds of cooking, add the spinach and then drain and rinse quickly in cold water.
Return noodles, edamame and spinach back to the pan and add the sauce. Toss together with the sauce until well coated, then divide into bowls and garnish with scallions and peanuts.