Preheat the oven to 350ºF. Coat a 8x8 baking dish with cooking spray.
In the bowl of a stand mixer fitted with the paddle attachment, combine sugar, oil, and flour until the mixture resembles wet sand. Turn the mixer to low and add cocoa, zucchini, vanilla, salt, and baking soda. Mix until well combined. Using a rubber spatula, stir in the chocolate chips.
Pour the batter into the prepared pan and bake for 45 minutes or until a toothpick inserted in the center comes out with moist crumbs clinging.
Remove from the oven and let cool on a wire rack. Cut into squares and serve.
If after mixing your batter still seems dry and sandy, you've removed too much liquid from your zucchini. You can bake as-is and get a still delicious but kind of weird treat, or you can add water a few table spoons at a time until a thick and creamy batter is achieved.