In a large saucepan cook 1/2 cup chopped onion and 2 minced garlic cloves in hot oil over medium heat about 5 minutes or until onion is tender. Stir in two 14-1/2-ounce cans chicken broth. Bring to boiling; add 1-1/2 cups uncooked rice, 1/2 teaspoon dried oregano, 1/8 teaspoon paprika, and salt and pepper to taste. Simmer, covered, about 40 minutes or until rice is tender. Remove from heat and stir in one 14-1/2-ounce can diced tomatoes, drained; one 11-ounce can whole kernel corn; and, if desired, 2 tablespoons snipped fresh cilantro.
Preheat oven to 400 degrees F. Slice tops from 8 small (or 4 large) sweet peppers; remove and discard seeds. In a 3-quart rectangular baking dish, arrange peppers in a single layer. Spoon rice mixture into peppers. If desired, place pepper tops on filling. Bake, covered, about 30 minutes or until peppers are crisp-tender and rice mixture is heated through. For more tender peppers, increase the baking time to 40 to 45 minutes.