Soak beans in cold water for at least some hours ( I did it for 4 hours).
Cook them followinf the box's instructions, I used pressure pot, no salt, for about 30 minutes.
Drain well the beans, let them cool then store in fridge.
In a bowl mix chopped coriander, vinegar, lime juice, garlic, chili and a teaspoon of salt.
Add oil, mix and set aside.
In a big bowl mix beans, tomatoes, bell pepper, onion.
Season them with the oil mixture and let it rest in fridge for at least 4 hours ( overnight is better).