Rinse the beans cold, drain and crush them coarsely with a fork. Wash the tomatoes and cut them into slices. Cut chilli rings into small pieces. Mix with tomatoes and beans.
Toast the slices of bread as desired. Halve the avocado, remove the core and remove the flesh. Mash with a fork.
Spread the avocado on the breads. Add the tomato and bean mixture and 1 tsp. yoghurt each, season with salt and pepper.