In a large bowl, mix the drained beans with the celery and sweet pepper. Roast the cashew nuts, in a dry frying pan, until browned. Put on paper towels and allow to cool. When cool, toss into the beans with the green onions. Mix the tomato sauce, garlic, salt, pepper, cumin, vinegar and olive oil together well. Pour over the beans and mix well. Allow to stand for about an hour, before serving.