Add 1 cup water to a microwave-safe bowl. Microwave 1.5 minutes or until boiling. Add sun dried tomatoes. Let stand 5 minutes.
Chop olives and slice mushrooms.
Place walnuts in a medium skillet over medium heat. Cook 5 minutes or until toasted, stirring frequently. Remove from skillet and set aside.
In same skillet, cook mushrooms over medium high heat. Cook 5 minutes. Add green beans and cook 5 additional minutes or until green beans are crisp-tender, stirring frequently.
Add olives, tomatoes, lemon juice, and salt; heat 1-2 minutes or until hot.
Sprinkle with walnuts and serve.