Combine agave, lime juice, 1 teaspoon lime peel, salt, rosemary and pepper; mix well. Sprinkle chicken breasts with salt and pepper to taste. Bake at 375°F for 30 minutes; brush with agave mixture and bake 15 minutes longer or until juices run clear. Remove chicken from baking pan; pour remaining sauce into pan and deglaze. Strain mixture into small saucepan; bring mixture to boil. Combine cornstarch and water; add to strained sauce. Cook and stir until mixture comes to boil. Boil 1 minute. Stir in remaining lime peel. Slice chicken breast; pour hot sauce over slices.