Heat the oil in a deep skillet over medium heat and add the onion. Cook until softened, about 6 minutes. Add the garlic, followed by the cumin, cinnamon, oregano, cayenne, smoked paprika, and salt and stir to combine. The mixture will be pasty. Add the sweet potato, stirring to coat with the aromatics and spices. Cook for an additional 3 to 5 minutes over medium-low heat, allowing the ingredients to get acquainted with one another.