Rinse quinoa thoroughly by placing in a fine-mesh strainer and holding under cold running water until water runs clear; drain well.
In 2-quart saucepan, heat 2 cups of the water to boiling over high heat. Add quinoa; reduce heat to low. Cover; simmer 10 to 12 minutes or until water is absorbed.
Meanwhile, in 12-inch skillet, heat remaining 4 cups water and bouillon cube to boiling over high heat. Add salmon, skin side up; reduce heat to low. Cover; simmer 10 to 12 minutes or until fish flakes easily with fork. Remove with slotted spoon to plate; let cool. Discard water. Remove skin from salmon; break into large pieces.
Meanwhile, rinse and dry skillet. Melt butter in skillet over medium heat. Add asparagus; cook 5 minutes, stirring frequently. Stir in onions; cook 1 minute, stirring frequently. Stir in peas, tomatoes and broth; cook 1 minute.
Gently stir quinoa, salmon, lemon-pepper seasoning and dill weed into asparagus mixture. Cover; cook about 2 minutes or until thoroughly heated.