In a medium salad bowl, mix vinegar, oil, sugar, salt, and pepper.
Peel cucumbers and trim the ends. Cut cucumbers lengthwise. Scrape out the seeds with a spoon. Dice and place in the vinegar mixture.
Add diced tomatoes, squash, and onions, then place them in the bowl with cucumbers. Add basil and mix well.
Courtesy of Game and Garden and Happy Healthy Family Tracking the Outdoors In. There are a ton of simple delicious recipes in this cookbook!