Cool Pinto Bean Puree
Combine the beans, canned tomatoes, scallions, and cilantro or parsley in a food processor or blender and process until well pureed. Transfer to a large serving container and stir in the lemon juice, chili powder, and cumin.
Place the green pepper and fresh tomatoes in the food processor and pulse on and off 2 or 3 times. Add the olives and pulse on and off quickly, 2 or 3 times more, or until the vegetables are finely chopped (approximately 1/4-inch pieces).
Stir into the bean puree, then add the chilies if desired. Stir in enough stock or water to achieve a medium-thick consistency. Serve at once or cover and refrigerate until needed.