1. Grate rind from lemon to make 1 teaspoon. Halve lemon; squeeze lemon to make 1 tablespoon lemon juice. Stir together the lemon juice, honey and mustard in a medium-size bowl. Add the scallops; toss to coat. Cover and refrigerate for 20 minutes.
2. Heat broiler.
3. Prepare the couscous following the package directions, but omitting the oil; when you add the couscous to the boiling water, add the spinach and lemon rind also.
4. Thread the scallops onto the metal skewers, dividing equally. Pour the remaining marinade into a small saucepan; boil the marinade for 3 minutes.
5. Coat the broiler-pan rack with nonstick cooking spray. Place the skewers on the broiler-pan rack.
6. Broil skewers about 3 inches from heat for 4 minutes a side or until cooked through, basting with the marinade.
7. Equally divide the couscous among 4 dinner plates; top each with the scallops.