In a medium-size bowl, whisk together vinegar, salt, black pepper, Dijon mustard, and honey until smooth. Gradually whisk in the olive oil and continue whisking until thickened. Set aside. Cut mozzarella into 1/2-inch pieces. Set aside.
Bring a medium-size pot of salted water to a boil. Add beans and cook for 5 minutes. Drain beans and place in a glass bowl. Toss with 1/4 cup of the dressing. Allow to cool to room temperature
Slice tomatoes in half. In a large bowl, toss together tomatoes, lettuce, mozzarella, beans and 1/4 cup of the dressing.
Serve salad immediately with the remaining dressing on the side.