Drain the noodles, add them to the saucepan and cook over moderate heat just until tender, about 3 minutes. Add the pork, vinegar, soy sauce and chile-garlic sauce and simmer until the pork is nearly cooked through, about 2 minutes. Add the snow peas, scallions and cornstarch mixture and cook until the vegetables are crisp-tender, about 1 minute. Stir in the sesame oil and season with salt. Ladle the soup into bowls and serve.