Sprinkle both sides of the salmon fillet with black pepper.
Place the salmon fillet on a grill rack or broiler pan coated with cooking spray, and grill the salmon for 5 minutes on each side or until the fish flakes easily when tested with a fork. Flake the salmon.
Cut off the tops of the corn kernels, and scrape the corn milk and remaining pulp from the cobs using the dull side of a knife blade. Set the corn kernels and corn milk aside.
Combine 3/4 cup milk and onion slices in a large saucepan. Bring the milk mixture just to a boil over medium heat; cover, reduce heat, and simmer 5 minutes. Discard the onion.
Add the corn and corn milk to pan, and cook 5 minutes, stirring frequently.
Combine the flour and 1/4 cup milk in a small bowl, and stir flour mixture well with a whisk.
Add flour mixture, salt, and white pepper to corn mixture in pan, and stir well. Cook 7 minutes or until thick, stirring constantly.
Remove from heat, and gently stir in salmon and dill.