In a mixing jar, combine lemon juice, olive oil, minced garlic, Dijon mustard, salt, and black pepper. Shake vigorously for about 30 seconds until emulsified.

Finely chop tomatoes, cucumbers, red onion, parsley, and mint, and place in a large bowl.

Gently fold the white beans into the bowl with the chopped vegetables.

Drizzle most of the dressing over the salad mixture. Toss gently to coat all ingredients.

Transfer to a serving bowl and drizzle with remaining dressing. Garnish with mint or parsley if desired.