Place salmon in a 13 x 9-inch baking dish. Combine onion and the next 8 ingredients (onion through thyme); pour over salmon. Cover and marinate in refrigerator 2 hours, turning occasionally.
Preheat oven to 350º.
Place cereal and pecans in a baking pan. Bake at 350º for 7 minutes or until toasted. Place mixture in a food processor; pulse 4 times or until finely chopped.
Remove salmon from marinade; reserve marinade. Arrange the salmon diagonally on a broiler pan coated with cooking spray. Sprinkle with 3/4 teaspoon salt. Combine 2 tablespoons of sugar, honey, and 1 1/2 teaspoons water, stirring with a whisk. Spread honey mixture over salmon; sprinkle with cereal mixture, gently pressing into salmon. Bake at 350º for 20 minutes or until fish flakes easily when tested with a fork.
While salmon bakes, place reserved marinade in a small saucepan. Discard tarragon and thyme. Bring marinade to a boil over medium-high heat; cook until reduced to 3/4 cup (about 10 minutes). Serve sauce with salmon.