Add all the ingredients to a medium bowl and gently toss to combine. Taste and add more salt as needed.
Cover and refrigerate for 15 minutes before serving.
Notes
Cucumber. You can use either regular or English cucumbers. I prefer English cucumbers for a crunchier texture, but regular ones also work just fine.
Let it marinate. Like pico de gallo, this dish tastes better the longer it sits, as the flavors have more time to meld. I recommend letting it chill for at least 15 minutes, but it’s best after 1 hour.
Storage. Place in an airtight container in the refrigerator for up to 5 days.