Preheat your oven to 350°F (175°C) and grease two 8×4 inch loaf pans.
Grate the zucchini and gently pat with paper towels to remove excess moisture, but don't squeeze too hard.
In a medium bowl, whisk together flour, salt, baking powder, baking soda, and cinnamon until evenly combined.
In a large bowl, beat eggs, oil, sugar, and vanilla until the mixture becomes light and slightly frothy – about 2 minutes with an electric mixer or 4 minutes by hand.
Gradually fold the dry ingredients into the wet mixture, stirring just until combined. When a few streaks of flour remain, fold in the grated zucchini and lemon zest.
Toss blueberries with 1 tablespoon of flour and gently fold them into the batter.
Pour the batter evenly into the prepared loaf pans, tapping them gently against the counter to release any large air bubbles.
Bake for 50-60 minutes, or until a toothpick inserted in the center comes out clean with a few moist crumbs. If the tops are browning too quickly, tent with aluminum foil after 40 minutes.
Allow to cool in the pans for 15 minutes before transferring to a wire rack to cool completely.