1 1/2 tablespoons cooking oil
1 small onion, chopped
4 cloves garlic, minced
1 1/2 teaspoons ground coriander
1/2 teaspoon ground ginger
1/4 teaspoon fresh-ground black pepper
1/8 teaspoon cayenne
1 quart canned low-sodium chicken broth or homemade stock
2 cups canned unsweetened coconut milk
5 teaspoons Asian fish sauce (nam pla or nuoc mam) or soy sauce
1 3/4 teaspoons salt
2 3-inch-long strips lime zest
1/2 pound egg fettuccine
1 pound boneless, skinless chicken breasts (about 3), cut into 14-inch slices
2 tablespoons lime juice
3 tablespoons chopped cilantro (optional)