Rinse salmon and pat dry with paper towels. Remove skin and bones; discard. Cut into 3/4 inch pieces. Cut tomato into 1/2 inch pieces. Coarsely chop onion. Set aside.Heat the wok over medium high heat until hot. Add butter and swirl to coat bottom. Add salmon and stir fry gently 3 to 4 minutes or until fish flakes easily when tested with a fork. Remove to a large bowl; cover and keep warm.Add tomato and onion to the wok; stir fry about 5 minutes or until onion is tender. Stir in flour until well mixed. Increase heat to high.Stir in broth and green beans; stir fry until sauce boils and thickens. Add salmon, half and half, salt, and pepper. Stir fry until heated through. Add half of the cheese to salmon mixture; toss until well mixed. Spoon salmon mixture over pasta. Sprinkle with remaining cheese. Garnish, if desired.