Rinse the beans thoroughly under cold water and drain them well. Pat dry with paper towels if they're very wet.
Chop all your vegetables into roughly similar-sized pieces so every bite has a good mix.
In a large bowl, combine the beans, tomatoes, cucumber, bell pepper, red onion, and parsley.
In a small jar or bowl, whisk together olive oil, lemon juice, minced garlic, oregano, salt, and pepper until well combined.
Pour the dressing over the bean mixture and toss everything gently but thoroughly.
Let it sit for at least 15 minutes before serving, or refrigerate for up to an hour for better flavor.
Taste and adjust seasoning with more lemon juice, salt, or pepper if needed.
