Open the canned white beans and pour them into a colander placed in the sink. Rinse the beans thoroughly under cold running water for about 30–40 seconds while gently tossing them with your hands. This removes excess starch and the metallic flavor sometimes present in canned bean liquid. After rinsing, allow the beans to drain completely for a minute so excess water does not dilute the dressing. Transfer the drained beans to a large mixing bowl and set aside.

Wash and dry the cherry tomatoes, cucumber, and parsley. Cut the cherry tomatoes in half lengthwise so their juices integrate easily with the dressing. Dice the cucumber into small cubes roughly 6–8 mm in size, ensuring the pieces are small enough to distribute evenly throughout the salad without overwhelming the beans. Finely dice the red onion into small pieces to prevent harsh onion bites. If the onion tastes very sharp, briefly rinse the diced onion under cold water and pat dry to mellow its intensity. Halve the Kalamata olives and add all prepared vegetables to the bowl with the beans.

Using a sharp knife, finely chop the parsley leaves and tender stems. Avoid crushing the herbs, as bruising can dull their bright flavor. The parsley should be finely chopped but still vibrant and leafy rather than pasty. Add the chopped parsley to the mixing bowl with the beans and vegetables.

In a small bowl, combine the fresh lemon juice, olive oil, za'atar spice blend, minced garlic, salt, and black pepper. Whisk the mixture vigorously for about 20–30 seconds until the olive oil and lemon juice emulsify slightly. The za'atar will disperse throughout the dressing, giving it a speckled green appearance and a fragrant herbal aroma. Taste the dressing and adjust the seasoning if necessary, adding a pinch more salt or lemon juice to balance acidity.

Pour the prepared za'atar dressing evenly over the beans and vegetables in the mixing bowl. Using a large spoon or salad tongs, gently fold the ingredients together until the dressing coats every component. Because white beans are delicate, mix carefully to avoid crushing them while still ensuring even distribution of the dressing.

Sprinkle the crumbled feta cheese over the top of the salad and fold it in very gently. The feta should remain in small crumbles rather than dissolving into the dressing, adding creamy bursts of salty flavor throughout the salad.

Allow the salad to rest at room temperature for 8–10 minutes before serving. This brief resting period allows the beans to absorb the lemon and za'atar dressing while the vegetables release a small amount of natural juice, creating a lightly emulsified dressing throughout the bowl.

Give the salad one final gentle toss before transferring it to a serving bowl. The salad can be served immediately at room temperature or lightly chilled. Garnish with an extra sprinkle of za'atar or chopped parsley if desired.