Cook pasta in boiling water 5 minutes. Add edamame; cook 6 minutes or until tender. Drain and rinse with cold water. Drain and place in a large bowl.
Heat a nonstick skillet coated with cooking spray over medium-high heat. Add salmon; cook 7 minutes or until fish flakes easily when tested with a fork, turning once. Coarsely chop salmon. Add to pasta mixture; toss gently to combine.
Heat oil in pan over medium-high heat. Add onion; sauté 4 minutes or until tender. Add spinach; cook 2 minutes or just until wilted, stirring frequently. Add spinach mixture and dill to pasta mixture; toss gently to combine. Add mustard, salt, and pepper; toss gently to coat.