Add lemon rind, rosemary, 1 tablespoon oil, 1 teaspoon garlic, and chicken to a resealable plastic bag. Gently shake to coat. Chill at least 1 hour.
Whisk together 1 tablespoon oil, 1 teaspoon garlic, lemon juice, salt, and pepper.
Thread chicken and zucchini in alternating pieces onto each of 12 skewers. Arrange skewers on a cooking spray coated grill rack. Grill 6 minutes per side or until chicken is fully cooked. Serve with lemon juice mixture drizzled overtop.