In a large mixing bowl, combine diced cucumbers, quartered cherry tomatoes, halved black olives, and finely diced red onion. Sprinkle in salt, pepper, and garlic powder. Stir gently until evenly coated.

Bring a large pot of salted water to a boil. Add spaghetti noodles and cook for 7-8 minutes until al dente. Drain and let cool for 5 minutes.

In a small bowl, whisk together the Good Seasons Zesty Italian dressing packet, red wine vinegar, and olive oil until well combined.

Once the spaghetti has cooled, add it to the vegetable mixture. Pour the dressing over the top, and toss everything together thoroughly.

Cover the bowl tightly with plastic wrap or transfer to an airtight container. Refrigerate for at least 4 hours before serving.