Cut beef steak lengthwise in half, then crosswise into 1/8 to 1/4-inch thick strips. Combine 2 tablespoons dressing and beef in medium bowl; toss to coat. Cover and marinate in refrigerator 30 minutes to 2 hours.
Heat large nonstick skillet over medium-high heat until hot. Add green beans and 1 teaspoon oil; stir-fry 5 minutes. Add tomatoes; stir-fry 2 to 3 minutes or until beans are crisp-tender and tomatoes begin to brown slightly. Remove from skillet; season with salt and pepper, as desired. Keep warm.
Add to same skillet, half of beef; stir-fry 1 to 3 minutes or until outside surface of beef is no longer pink. Remove from skillet. Repeat with remaining beef.
Divide spinach evenly among four plates. Top with beef and vegetables. Sprinkle with cheese. Drizzle with remaining 1/4 cup dressing.
Nutrition information per serving: 230 Calories; 81 kcal Calories from fat; 9 g Total Fat; 2.9 g Saturated Fat; 4 g Monounsaturated Fat; 72 mg Cholesterol; 448 mg Sodium; 12 g Total Carbohydrate; 3.2 g Dietary Fiber; 30 g Protein; 4.7 mg Iron; 5.9 mg Niacin; 0.6 mg Vitamin B6; 3.3 mcg Vitamin B12; 6.7 mg Zinc; 30.9 mcg Selenium; 110.9 mg Choline;