Preheat oven to broil. Place foil on cookie sheet and set aside.
Bring 1 3/4 cups water to a boil in a pot; add 1/4 teaspoon of the salt and the couscous. Cover and cook 8 minutes, stirring occasionally. Set aside.
Meanwhile, in a cup of small bowl combine crumbs and 1 tablespoon dill; set aside.
Sprinkle salmon with remaining 1/4 teaspoon salt and the pepper and place on cookie sheet. Place directly under broiler and cook for 5 minutes. Remove from oven and lower rack (6 inches from heat source).
Brush salmon with mustard and sprinkle with the crumb mixture, pressing to adhere. Spray with Pam. Return to oven and cook another 2 minutes.
Stir remaining dill, spinach and chicken broth into the couscous and let sit for 5 minutes before serving with the salmon.