Prep the produce: Dice the cucumber, halve the tomatoes, and thinly slice the red onion.
Rinse and drain the chickpeas well.
Make the dressing: In a small bowl or jar, whisk together olive oil, lemon juice, lemon zest, garlic, salt, pepper, oregano, and red pepper flakes. Taste and adjust lemon or salt as needed.
Combine the salad: In a large bowl, add cucumber, tomatoes, chickpeas, and red onion. Pour the dressing over the top.
Toss and rest: Gently toss until everything is coated.
Let it sit for 5–10 minutes so the flavors mingle.
Add herbs and feta: Fold in parsley and mint. Sprinkle in feta, if using, and give it one more light toss.
Finish and serve: Taste and add more salt, pepper, or lemon as needed. Serve chilled or at room temperature.