In a large skillet, heat the canola oil over medium-high heat; add the onions and cook until translucent. Add the cayenne, chile powder, cumin and Mexican oregano and cook, stirring, until fragrant, about 1 minute. Add the tomato paste and cook, stirring, for 2 minutes. Add the beef and cook until browned, 8 to 10 minutes. Stir in the tomato sauce and apple cider vinegar and cook until the sauce reduces slightly, 3 to 5 minutes.
Build the tacos in this order: cheese on the bottom, followed by the beef, tomatoes, avocados, lettuce and jalapenos. Serve the sour cream on the taco or on the side for dipping.