Thaw frozen seafood. Halve large scallops. Scrub mussels; remove beards. Combine 2 cups of the water and 3 tablespoons of the salt; soak mussels 15 minutes. Drain and rinse. Repeat twice.
Cook onion and garlic in hot oil until tender. Add cumin, cinnamon, and ground red pepper; cook and stir 1 minute. Stir in broth, tomatoes, saffron, and 1/4 teaspoon salt. Bring to boiling; add seafood. Return to boiling; reduce heat. Simmer, covered, 5 minutes or until shells open. Serve with couscous. If desired, top with parsley. Makes 4 servings.