Preheat your oven to 375°F (190°C).
In a skillet over medium heat, add the olive oil and diced yellow onion, sautéing until translucent.
Add the lean ground beef to the skillet, breaking it up with a spatula, and cook until browned.
Stir in the minced garlic, chili powder, ground cumin, sea salt, and black pepper, cooking for another minute until fragrant.
Warm the corn tortillas in a dry pan or microwave for 15 seconds until pliable.
Spread 2 tablespoons of tomato sauce on the bottom of a small baking dish.
Divide the beef mixture evenly between the two tortillas, roll them tightly, and place them seam-side down in the dish.
Pour the remaining tomato sauce over the tortillas and sprinkle with the shredded cheddar cheese.
Bake for 10-12 minutes until the cheese is melted and the sauce is bubbling.
Remove from the oven and let rest for 2 minutes before serving.