Rinse the beans in a colander and drain. Either thaw the corn or let it drain in the sieve. Core the tomatoes and cut into cubes. Core the avocado, use a spoon to remove the pulp from the skin and also cut into cubes. Peel the onion and chop finely.
Put all the ingredients in a bowl, squeeze the lime and add the juice with the vinegar and the chopped coriander leaves. Mix well and cover and leave to stand in the refrigerator overnight.
Season to taste with salt & pepper the next day.
If you don`t like coriander, you can also use flat-leaf parsley.
Tastes delicious as a starter with tortilla chips or as a main course with fried chicken breast.