Put the beans in a large sieve, rinse well under water, drain. Pat the tofu dry with a kitchen towel and cut into pieces half the size of a bean.
Cut the onion into very small cubes and place in a bowl with all the ingredients except the tofu and beans and stir well. Then add the beans and tofu, mix everything well, season to taste again and if you can, you can let the salad steep in the fridge a little longer.