In a med. pot of boiling salted water, cook orzo until al dente, according to pkg instructions. Drain well. Spread on a rimmed baking sheet to cool completely.
In a large skillet, heat 1 Tb oil over med. heat. Add zucchini and garlic; season with salt and pepper. Cook, tossing occasionally, until crisp and tender, 4-6 mins.
Transfer orzo to a med. bowl; add zucchini mixture, basil, vinegar and remaining tsp. of oil. Season with salt and pepper; toss to combine. Cover and refrigerate up to 1 day; bring to room temp. before serving.