Drain canned chickpeas and rinse them under cold water. Let them dry well so excess moisture doesn’t dilute the dressing. Place them into a large mixing bowl.
Dice cooked beets, cucumber, and red onion, then add them to the bowl with olives and minced garlic. Mixing colorful vegetables first helps distribute flavors evenly later.
Whisk olive oil, Dijon mustard, and red wine vinegar until smooth. Season lightly with salt and pepper so flavors blend nicely once mixed with vegetables.
Pour dressing over vegetables and chickpeas. Toss gently until everything is evenly coated without breaking the beets or chickpeas.
Sprinkle crumbled feta and fresh dill on top and gently fold them in. Taste and adjust seasoning before serving or chilling.