Preheat oven to 350F. Spray a 9 x 5" loaf pan and set aside.
In a large bowl, mix together flour, baking powder, and salt.
In a medium bowl, beat together eggs, melted coconut oil, and maple sugar. Add the buttermilk, lemon zest and lemon juice and blend everything together. Fold in grated zucchini and stir until evenly distributed.
Add the zucchini mixture to the dry ingredients and stir everything together, don't over mix.
Pour batter into prepared loaf pan and bake for 45 minutes, or until a toothpick inserted in centre of loaf comes out clean. Cool loaf in pan for 10 minutes, Then remove to a wire rack and cool completely.
While loaf is cooking, you can make the glaze.
For the glaze:
Mix together powdered sugar and lemon juice in a small bowl. Spoon glaze over cooled loaf. Let glaze set before serving.