Begin by thoroughly washing all vegetables under cold running water. Pat them dry completely with a clean kitchen towel or paper towels. Removing excess moisture helps the dressing adhere properly and prevents the salad from becoming diluted. Dry vegetables also maintain a crisper texture once the dressing is added.

Trim the ends of the cucumber and cut it lengthwise if necessary. Dice the cucumber into small cubes approximately 8–10 mm in size. If the cucumber has large seeds or a watery center, scoop out the seeds with a spoon before dicing to maintain a crisp texture. Transfer the diced cucumber to a large mixing bowl.

Cut the tomatoes into small cubes roughly the same size as the cucumber pieces. If the tomatoes are particularly juicy, gently remove some of the seed pulp to prevent excess liquid from watering down the dressing. Add the diced tomatoes to the mixing bowl with the cucumber.

Remove the stems and seeds from both bell peppers. Slice the peppers into thin strips and then cut them into small dice about 8–10 mm wide so they match the size of the other vegetables. This uniformity ensures every bite contains a balanced mix of ingredients. Add the diced yellow and red bell peppers to the bowl.

Peel the red onion and dice it finely so the pieces integrate smoothly throughout the salad. If the onion is particularly strong, briefly rinse the diced onion under cold water and pat dry with paper towels to mellow its intensity while preserving its crisp texture. Add the diced onion to the mixing bowl.

Rinse the parsley and mint thoroughly and shake off excess water. Finely chop the parsley leaves and tender stems using a sharp knife. Chop the mint leaves slightly more coarsely so they retain their aroma without turning dark or bruised. Add the herbs to the bowl with the vegetables.

In a small bowl combine the olive oil, fresh lemon juice, minced garlic, salt, and black pepper. Whisk the mixture vigorously for about 20–30 seconds until the dressing becomes lightly emulsified. The dressing should taste bright and balanced, with lemon providing acidity and olive oil adding smooth richness.

Pour the lemon vinaigrette evenly over the chopped vegetables. Using large salad spoons or tongs, gently toss the salad until all ingredients are lightly coated. Because the vegetables are diced small, they should distribute evenly with minimal mixing.

Let the salad sit for 4–5 minutes before serving. This short resting period allows the vegetables to absorb the dressing and develop a more cohesive flavor while still maintaining their crisp texture.

Give the salad one final gentle toss and transfer it to a serving bowl. The salad is best served immediately while the vegetables remain crisp and vibrant.