Wash and dry the cucumbers, then chop them into bite-sized pieces. Chop red and orange bell peppers and red onion into small pieces. If using, finely chop cilantro. Combine in a large mixing bowl.

In a separate bowl, whisk together lime juice, olive oil, chili powder, and salt and pepper until well blended.

Pour the dressing over the vegetables and gently toss to coat evenly.

Cover and chill in the refrigerator for 15 to 30 minutes to enhance flavors.

After chilling, toss gently and serve cold, optionally garnished with fresh cilantro.