couscous and feta-stuffed peppers

INGREDIENTS

• Vegetable-oil cooking spray
• 1 1/4 cups chicken or vegetable broth
• 2/3 cup couscous
• 4 large bell peppers, mixed colors
• 2 teaspoons olive oil
• 1/2 cup chopped onion
• 6 ounce zucchini, quartered lengthwise then sliced across thinly
• 6 ounce yellow squash, quartered lengthwise then sliced across thinly
• 1/2 tsp fennel seeds
• 1/2 tsp dried oregano
• 1/2 tsp salt
• 1 cup cherry tomatoes, cut in half
• 15 ounces canned chickpeas, drained and rinsed
• 4 ounces crumbled feta cheese (about 1 cup)
• 3 tablespoons tomato paste
• 2 red onions, sliced
• 1 cup cider vinegar
• 1 teaspoon salt