In small bowl, combine pork and Italian dressing; toss to coat. Let stand at room temperature for 10 minutes to marinate.
Meanwhile, in another small bowl, combine ranch dressing mix, mayonnaise and milk; blend well. Set aside.
Heat oil in large nonstick skillet over medium-high heat until hot. Add pork mixture; cook and stir until pork is no longer pink.
To serve, arrange lettuce on 4 individual dinner plates. Top each with broccoli, zucchini, tomato wedges and cooked pork. Drizzle dressing over salads.