In a small jar, combine lemon juice, olive oil, garlic, mustard, salt, and pepper. Seal and shake for about 30 seconds until emulsified.

In a large bowl, add beans, tomatoes, cucumber, onion, parsley, and mint.

Drizzle most of the dressing over the salad and toss gently to coat all the ingredients.

Let the salad rest at room temperature for about 15 minutes for flavors to meld.

Taste the salad and drizzle with reserved dressing if desired, then stir gently.

Transfer the salad to a serving bowl or platter, garnish with herbs, and serve immediately.