Peel the cucumbers if needed and then dice them into small pieces. Place them in a large bowl.
Slice the grape tomatoes in quarters and add them to the bowl.
Use a mandoline slicer to slice onions and then cut them into smaller pieces. Add them to the bowl.
Stir the vegetables to combine.
In a small bowl, whisk together the rice vinegar, granulated sugar, chopped dill, sea salt, and black pepper.
Pour the dressing over the salad and stir to coat. Cover and refrigerate for at least 15 minutes or until ready to serve.
Video
Notes
One: Make Ahead
If prepared ahead of time you can drain the excess liquid/dressing before serving.
Two: Storage
Three: Creamy
Stir in 1/4-1/2 cup of sour cream, greek yogurt, or mayo.
Four: Panera Tomato Basil Cucumber Salad
Add 1/2 cup of chopped or thinly sliced fresh basil. Omit the onion if desired.
Five: Mediterranean
Stir in 4 ounces of crumbled feta cheese and 1/4 cup of chopped fresh parsley. Add 1/3 cup of olive oil to the dressing and omit the fresh dill. You can also substitute the rice vinegar with lemon juice if you want to.