Fava Beans with Tomato and Onion

Ingredients

• 4 1/2 pounds unshelled fava beans (about 2 1/4 cups shelled)
• 2 cups sliced, halved plum tomatoes (about 4)
• 1 cup vertically sliced sweet onion
• 1 tbsp red wine vinegar
• 2 tsp extravirgin olive oil
• 1 tsp minced fresh garlic
• 1/4 tsp salt
• 1/4 tsp freshly ground black pepper
• Cooking spray
• 1/2 tsp sugar
• 1/2 tsp red wine vinegar
• 1/8 tsp salt