Cook rice according to package directions. Place 1 1/2 cans of beans in food processor (including juice). Blend until smooth. Pour into large saucepan. Add remaining beans, water, onions, dressing mix and cumin (for an extra kick add a teaspoon of chilli powder and cayenne pepper to taste). Stir until blended. Bring to a boil on medium high heat. Reduce heat and simmer 5 minutes. Add rice. Garnish with a bit of sour cream, chopped tomatoes and fresh cilantro (if desired).