Step 1: Prepare the Vegetables
First, wash all your vegetables thoroughly under cool running water and pat them dry.

• Tomatoes: Core the tomatoes and chop them into bite-sized wedges or chunks, about 1-inch in size. If using cherry or grape tomatoes, you can simply halve them. Place the chopped tomatoes in a large mixing bowl.
• Cucumber: If using an English cucumber, there’s no need to peel it as the skin is thin and adds a nice color and texture. If using a standard cucumber with a thick, waxy skin, you may want to peel it partially or fully. Slice the cucumber into thin rounds, about 1/8-inch thick. For an even crunchier salad, you can “sweat” the cucumbers by placing the slices in a colander, sprinkling them with a bit of salt, and letting them sit for 15-20 minutes. This draws out excess water. Rinse them lightly and pat them dry before adding to the salad.
• Onion: Peel the red onion and slice it as thinly as possible. A mandoline slicer is excellent for this, but a sharp knife works just as well. To reduce the sharp “bite” of the onion, you can soak the slices in a bowl of ice water for about 10 minutes, then drain and pat them dry.

Step 2: Combine the Salad Ingredients
Add the prepared cucumber slices and thinly sliced red onion to the large bowl with the tomatoes. If you are using fresh herbs like dill, parsley, or basil, add them now. Gently toss the vegetables together to distribute them evenly.

Step 3: Whisk the Vinaigrette
In a separate small bowl or a glass jar with a lid, combine the extra virgin olive oil, red wine vinegar, granulated sugar (if using), 1 teaspoon of sea salt, and 1/2 teaspoon of freshly ground black pepper. Whisk vigorously until the dressing is well-emulsified (it should look slightly creamy and uniform). If using a jar, simply seal the lid and shake it well for about 30 seconds.

Step 4: Dress and Marinate the Salad
Pour about two-thirds of the vinaigrette over the vegetables in the large bowl. Gently toss everything together until the vegetables are evenly coated. Taste the salad and add more dressing, salt, or pepper as needed. For the best flavor, cover the bowl and let the salad marinate in the refrigerator for at least 30 minutes. This allows the vegetables to absorb the flavors of the dressing and release some of their own juices, creating a delicious brine at the bottom of the bowl.

Step 5: Final Toss and Serve
Just before serving, give the salad one final gentle toss to redistribute the dressing and the accumulated juices. Serve chilled.