Heat oil in 4 quart pot over medium-high heat. When hot, add red onion and rice. Cook until rice is lightly browned, about 4 minutes, stirring often to prevent burning. Add broth, beans, corn and cumin. Bring to a boil. Simmer, covered, until rice is tender, 15 to 18 minutes. Add spinach leaves, cilantro, green onion and salsa. Stir well. Adjust liquid with water as needed. Add salt and pepper to taste.