Combine the cucumbers, tomatoes, onions, cilantro, jalapeños, garlic, lime juice, olive oil, salt, and black pepper in a large bowl. Toss together to coat, taste, and season with more salt and black pepper as needed.
Cover and refrigerate for 30 minutes to let all the flavors meld together.
Serve with tortilla chips or on tacos, lettuce wraps, salads, fish, or any dish that needs a hint of freshness and brightness.