Using a spoon, scoop out the interior of the zucchini halves and place them in the prepared baking dish. Each half should have a 1⁄4-inch thick shell. Remove what is extracted from each half.
Meanwhile, heat a medium-sized skillet over medium heat. Add 1 tablespoon oil, ground chicken or beef, onions, salt, and pepper. Cook for 7 minutes or until the chicken is cooked through.
Remove the skillet from the stove and add corn, beans, salsa, bell peppers, jalapeños, garlic, chili powder, ground cumin, and oregano. Mix until fully combined.