Prepare the Vegetables: Wash and slice the English cucumber, garden-fresh tomatoes, and sweet onion. Cut the cucumber into thin rounds or half-moons, the tomatoes into wedges, and the onion into thin slivers. Gather all the fresh vegetables in a large mixing bowl.

Make the Dressing: In a medium mixing bowl, whisk together white vinegar, vegetable or olive oil, water, sugar, salt, and freshly ground pepper until combined.

Combine and Toss: Pour the dressing over the bowl of sliced vegetables and gently toss to ensure each piece is well coated.

Chill for Flavor Development: Cover the bowl and place it in the refrigerator for at least one hour to allow flavors to meld.

Serve and Enjoy: Give the salad a gentle toss before serving. Garnish with fresh herbs if desired.