Heat the oil in a large skillet over medium heat. Add the onion and cook, stirring often, until onion is softened and translucent, about 4 to 5 minutes. Add the beef and cook, breaking the meat up into smaller pieces, until cooked through, about 5 minutes. Drain the fat from the pan.
Stir in the garlic, chili powder, cumin, coriander, salt, and pepper. Cook for about 30 seconds before adding tomato sauce and jalepeno. Reduce heat to low and simmer for 10 minutes, stirring occasionally. Serve meat in taco shells with desired toppings.