In large nonstick ovenproof skillet, heat oil over medium heat; cook onion, zucchini and garlic, stirring often, for 5 to 8 minutes or until softened.
Meanwhile, in large bowl, whisk together eggs, milk, salt and pepper; stir in red pepper and dill. Pour into skillet; reduce heat to medium-low.
Sprinkle with cheese and olives; cook for 10 minutes or until bottom and side are firm yet top is still slightly runny. Broil for 3 to 5 minutes or until golden brown and set. Cut into wedges.