1. Whisk dressing ingredients and 1/4 tsp pepper in bowl until blended. Cut beef tenderloin tips into 1" x 1/2" pieces.
2. Heat oil in large nonstick skillet over medium-high heat until hot. Stir-fry 1/2 of beef2 to 3 minutes or until surface of beef is no longer pink; remove. Repeat with remaining beef. Season with salt and pepper.
3. Toss greens with 1/2 cup dressing. Top with beef and croutons. Serve with remaining dressing.