Preheat oven to 325 degrees F (165 degrees C). Grease an 8x4 inch loaf pan.
In a bowl, beat together the zucchini, sugar, egg, and oil. In a separate bowl, sift together the flour, salt, baking soda, and baking powder; stir in the cinnamon and lemon zest. Stir the flour mixture into the zucchini mixture just until blended. Pour the batter into the prepared pan.
Bake 45 minutes in the preheated oven, until a knife inserted in the center comes out clean. Remove from heat, and cool about 10 minutes before turning out onto a wire rack to cool completely.