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