Hot Sesame Noodles with Pork

Name: Hot Sesame Noodles with Pork
Ingredients: 1 pound spaghetti; 1/4 teaspoon table salt , plus salt for cooking pasta; 2 tablespoons toasted sesame oil; 8 ounces ground pork; 1/4 cup soy sauce , divided; 5 teaspoons hoisin sauce , divided; 1 tablespoon dry sherry; 1/4 cup tahini; 2 tablespoons rice vinegar; 1 tablespoon Asian chili-garlic sauce; 2 teaspoons sugar; 1/4 cup vegetable oil; 6 scallions , white parts sliced thin, green parts sliced thin on bias; 3 garlic cloves , minced; 1 teaspoon red pepper flakes; 1/2 teaspoon ground Sichuan peppercorns , plus extra for serving (optional)