Heat oil in med saucepan over med-high heat. Add corn to pan; cook 10 min or til it starts to brown, stirring occasionally. Remove from pan. Set aside.
Melt butter in pan. Add onions; saute 5 min or til tender. Stir in rice, cumin, and garlic; cook 1 minute Add broth, pepper, salt and diced tomatoes to pan; bring to a boil. Cover, reduce heat, and simmer 45 min, stirring occasionally. Remove from heat; stir in reserved corn and beans. Cover and let stand 10 minute Stir in cilantro and juice and serve.