Heat butter in a small saucepan over medium heat; cook 3 minutes or until browned. Add nuts; cook 1 minute, stirring occasionally. Add couscous; cook 1 minute, stirring occasionally. Add wine and broth; bring to a boil. Cover, remove from heat, and let stand 5 minutes. Fluff with a fork; stir in lemon rind and juice, 1/4 t salt, and black pepper.
Combine white pepper, ground fennel, coriander, sugar and 1/4 t salt in a small bowl. Coat salmon fillets with cooking spray. Sprinkle fillets with spice mixture. Place salmon on a grill rack coated with cooking spray. Grill over medium heat 4 minutes on each side or until desired degree of doneness.