Finely chop the red onion and place it in a mixing bowl. Slice Persian cucumbers in half lengthwise and chop into small pieces. For Roma tomatoes, cut in half, scoop out the seeds, and chop finely.

In a small bowl, squeeze fresh lemon juice to gather about 3 tablespoons. Add dried mint, salt, and pepper, and mix thoroughly.

Combine the chopped cucumbers, Roma tomatoes, and red onion in a large mixing bowl. Toss gently to mix, and then pour the dressing over the salad.

Drizzle olive oil over the salad and gently toss one last time before serving.