In large bowl, toss potatoes, orange peppers, onion and 2 tablespoons Hellmann's® or Best Foods® Real Mayonnaise. On large baking sheet, evenly arrange potato mixture. Roast, stirring occasionally, 35 minutes or until potatoes are tender; cool slightly.
In large bowl, gently toss potato mixture, avocado, cilantro and remaining Mayonnaise (1/2 cup). Season, if desired, with salt and ground black pepper. Serve warm or at room temperature.