From previous night soak the beans in a bowl filled with water, the water to be at least 4 cm above the beans as they increase their volume quite rapidly. Add more water if needed.
Next day place a medium pot or casserole on high fire filled with water. Bring to a boil and add the beans along with the bay leaves. Bring again to a boil and simmer on low heat with the lid on for about 45’ for the beans to soften. Remove from the fire, discard the bay leaves, drain and keep aside to cool.
To make the dressing mix the oil with the lemon juice, vinegar and mustard. Whisk well and keep aside.
Toss in a serving bowl the rest of the ingredients, except of the avocado, along with the beans, season with the salt and pepper pour the dressing and mix gently. Finally, add the avocado and toss gently.