Prep the cucumbers. Run the tines of a fork down the sides of each cucumber, scoring the skin. This is an optional step, but helps the dressing stick to the cucumbers.
Salt. Thinly slice cucumbers and place in a large bowl along with the chopped tomatoes and thinly sliced red onions. Sprinkle with the salt, toss and let sit while you prepare the remaining ingredients, about 10-30 minutes.
Strain. Pour the cucumbers, tomatoes, and onions into a strainer to drain any liquid but don't rinse.
Mix. Return cucumbers, tomatoes, and onions to the large bowl. Add the bell pepper, scallions, mint, lime juice, olive oil, oregano, and chile powder. Toss to combine. Taste and add more salt if you'd like. Adjust the level of chile powder to your liking.
Enjoy! Refrigerate until ready to serve. This is best served the same day but will keep up to 3 days.