Marinated cucumbers, onions, and tomatoes are a beautiful thing and are bountiful most of the year, though they are truly best "in season". I like this so much more than a traditional lettuce or mayonnaise salad with BBQ or grilled meats. The slight tang and the sweetness of the dressing combined with the crunch of the lightly pickled veggies is perfect on a warm day. It also keeps better for picnics that just about anything else.
This dressing isn't complicated or a secret. There are no off the wall ingredients and is just perfect.
1 cup of water
1/2 cup distilled white vinegar (other vinegar can be considered, but apple cider is probably too tart)
1/4 cup white sugar
1/4 cup vegetable oil (not olive as it will flavor the veggies)
2 teaspoons salt
1/2 Tablespoon black pepper (the original calls for 1T. Do what you want.)
sliced cucumbers (no need to remove seeds, but I prefer peeled. You can also score the skin)
sliced tomatoes (roma or similar work well)
half a sliced yellow onion (or white if you like more bite)
Mix all of the ingredients in a bowl and whisk until the sugar is dissolved. You can also combine this in an air-tight container and shake it up.
Only add enough veggies to be covered by the dressing.
Experiment with this by adding sliced carrots or sweet peppers!