Mix bean marinade:
In a large bowl, mix white beans, lemon juice, olive oil, garlic, oregano, salt, and black pepper. Stir delicately and allow to sit for 15 to 20 minutes.Prep vegetables:
As the beans rest, cut cucumber into small cubes, halve cherry tomatoes, slice red onion thinly, and chop parsley.Combine with beans:
Toss cucumber, tomatoes, onion, olives, and parsley into the bean mixture. Stir gently until everything is evenly coated.Fold in feta:
Carefully fold in the feta cheese to preserve its crumbly texture.Serve or chill:
Present right away or refrigerate for 20 to 30 minutes prior to serving to enhance flavor.