Combine lentils, tomatoes, cucumber, olives, onion, feta and ¼ teaspoon each salt and pepper in a large bowl; set aside.
Whisk vinegar, shallot, garlic, honey and the remaining ¼ teaspoon each salt and pepper in a small bowl. Gradually whisk in oil until well combined. Gently stir the dressing into the lentil mixture. Serve immediately or cover and refrigerate for up to 5 days.
