Rinse and drain canned beans thoroughly to remove excess sodium. If using dried beans, soak them overnight and boil until tender.

Finely dice red onion and bell peppers, then combine in a mixing bowl.

Whisk together olive oil, red wine vinegar, salt, pepper, and oregano in a separate bowl until well combined.

Combine prepared beans, chopped vegetables, and fresh herbs in a large mixing bowl. Pour the dressing over and toss gently for even coating.

Let the salad sit at room temperature for at least 30 minutes to allow flavors to meld together.

Serve immediately or store in airtight containers in the fridge for up to a week.