In a large saucepan, bring broth to a boil. Stir in couscous. Remove from the heat; cover and let stand for 5-10 minutes or until broth is absorbed.
Fluff with a fork. Stir in the beans, corn, red pepper, onions and cilantro. In a small bowl, whisk the oil, lime juice, vinegar, cumin, salt and pepper. Drizzle over salad and toss to coat. Sprinkle with pine nuts if desired. Yield: 6 servings.