Slice the zucchini into 1/4-inch rounds—uniform thickness ensures even marinating and a better texture throughout the salad. Thinly slice the celery on a bias, which creates an elegant presentation and increases surface area for the dressing to penetrate. Finely dice the red onion and green bell pepper into similar-sized pieces so everything cooks and flavors evenly. Add all prepared vegetables to a large mixing bowl.

In a small bowl, combine the sugar, rice vinegar, wine vinegar, vegetable oil, and water. Crush the dried basil between your palms to release its essential oils—this step makes a noticeable difference in flavor intensity. Add the salt, black pepper, and red pepper flakes, then whisk everything together until the sugar is completely dissolved and the dressing is well emulsified. I find that a bit of whisking helps the flavors meld better than just stirring.

Pour the dressing from Step 2 over the vegetables in the bowl and toss everything together until the vegetables are evenly coated. Make sure to get all the liquid distributed throughout so every bite carries the flavor. Cover the bowl and refrigerate for 1 to 2 hours—I recommend at least 90 minutes so the vegetables have time to soften slightly and absorb the dressing's flavors. The longer it sits, the more flavorful it becomes, and the vegetables will release their own juices to meld with the dressing.