In the meantime, heat the oil in a large skillet over medium heat. Add the onion, garlic, salt, oregano, pepper and cumin, and sauté until the onion is soft and translucent, about 5 minutes. Add the ground turkey, breaking it up so there are no lumps, about 3-5 minutes. Stir in the tomatoes and corn, and bring to a simmer. Cook covered until most of the liquid has evaporated and the turkey is cooked through, about 10-15 minutes. Adjust the seasoning to taste.