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.
Recipe courtesy of Jeff Mauro