In a large skillet, heat olive oil over medium-high heat. Stir in the diced onion and ground turkey. Cook for approximately 5 minutes, or until the turkey is browned and the onion becomes soft.
Add the minced garlic, tomato sauce, ground cumin, chili powder, dried oregano, paprika, cayenne pepper (if desired), and salt. Stir thoroughly before putting the mixture into your slow cooker.
Put the lid on the slow cooker and cook on high for 2-3 hours, allowing the flavors to blend. Once ready, serve the turkey taco meat in warm corn tortillas topped with your favorite ingredients.