Drain and rinse the kidney beans, cannellini beans, and chickpeas under cold running water. Let them drain thoroughly, then transfer them to a large mixing bowl.

Wash and dry the produce. Finely chop the green bell pepper and celery, thinly slice the red onion, halve the cherry tomatoes, and chop the parsley. Add everything to the bowl with the beans.

In a small bowl, whisk together the olive oil, apple cider vinegar, lemon juice, honey or maple syrup, Dijon mustard, garlic, oregano, black pepper, and salt until well combined.

Pour the dressing over the beans and vegetables. Toss gently until everything is evenly coated.

Cover and refrigerate for at least 30 minutes. If time allows, chill for 1 to 2 hours to give the flavors more time to mingle.

Toss gently again and garnish with extra chopped parsley if desired. Serve chilled or let individual portions sit briefly at room temperature before serving.