Add the red wine vinegar, garlic, sugar, Italian seasoning, salt, black pepper, and crushed red pepper (if using) to a jar or container with a tight-fitting lid. Stir well. Slowly stream in the olive oil while stirring with a fork or small whisk. Cover tightly and shake vigorously until the dressing is blended and emulsified. Refrigerate until ready to use. Shake again before each use, as separation may occur.

Cook the orzo according to the package directions until al dente, usually 8–10 minutes. Drain using a fine mesh strainer (regular colanders may let the orzo slip through the holes).

Transfer the hot orzo to a large bowl and immediately toss with 1–2 tablespoons of the prepared dressing to infuse flavor and prevent sticking. Let it cool while you prepare the vegetables.

Once the orzo is cool, add the tomatoes, zucchini, onion, crumbled feta, dill, and parsley. Toss well to combine.

Add more dressing and toss until everything is evenly coated. Reserve a tablespoon or two to add just before serving. Some of the dressing will be absorbed as the salad chills, and a final drizzle helps loosen it up and adds a nice glossy finish.

Cover and refrigerate until chilled, at least 1 hour. Toss again with the reserved dressing right before serving.