Rinse the beans. Cut off a small bit from both ends. Then cut vertically if flat and wide. If long cut into half in the middle.
Grate the onions or use a food processor.
Grate the tomatoes or use a food processor.
Put all the ingredients at once in a pressure cooker or a pot.
Mix well to blend.
Start cooking for about 8 minutes until everything is well combined and the beans are some what sautéed. This will help you get all the flavors of everything; the sweetness of the beans and the aroma of the tomatoes.
If the tomato has left some water, additional water is not necessary. If not add water just enough to cover the bottom.
Cover the lid. Cook until the beans are done.
This dish gets better the next day. Keep in the fridge and serve cold as a side dish.