Place the beans in a saucepan with enough water to cover them by 1 inch. Bring beans to a slow boil. Reduce heat to low and simmer until tender, but not mushy ( about 35 minutes). Set aside to cool. When the beans have cooled, place them in a large bowl. Add the celery, carrots, parsley, white onion and mint; toss to blend. For Dressing: blend olive oil, orange and lemon juice, garlic, coriander, salt, pepper, and brown sugar in a blender for 6 seconds. Transfer to a small saucepan and simmer over low heat for 5 minutes. Remove from heat and cool. Pour dressing over the bean salad and refrigerate for at least 1 hour before serving.