Heat the oil in a large saucepan. Add the cumin seeds, oregano, onion, celery and chilli and cook gently, stirring, for about 6–8 minutes until the vegetables start to colour.
Add the canned tomatoes, sun-dried tomatoes, sugar, stock, beans and coriander and bring to the boil. Reduce the heat and simmer for about 20 minutes until the juices are thickened and pulpy.
To make the salsa, finely dice the avocado and put it in a small bowl. Halve the tomatoes, scoop out the seeds and finely dice the flesh. Add to the bowl with the chilli sauce and lime juice. Mix well.
Season the bean mixture and spoon into bowls. Top with spoonfuls of soured cream and the avocado salsa. Serve with toasted pitta or flat breads.