1. Place the finely diced cucumber in a colander, and sprinkle with salt. Toss and allow to sit for 15 minutes. Rinse the cucumber with cold water, and drain on paper towels. Place onion in a bowl and cover with cold water. Let sit for five minutes, then drain, rinse with cold water and drain on paper towels.
2. Combine the tomatoes, chiles, cilantro, vinegar, lime juice and olive oil in a bowl. Add the cucumber and onion, season to taste with salt, and add the caulirice and cilantro. Toss together.
3. Serve garnished with sliced avocado.