Trim ends from the carrots and zucchini. Use a vegetable peeler to make long thin strips down the length of each carrot and zucchini, making long ribbons.
Place carrots in a steamer basket. Place in a large saucepan over 1 in. of water; bring to a boil. Cover and steam for 2 minutes. Add zucchini; cover and steam 2-3 minutes longer or until vegetables are tender. Transfer vegetables to a bowl. Add the lemon juice, oil, salt and pepper; toss to coat.