In a large skillet over medium-high heat, add the oil and ground beef. Break the meat and sauté for 5-7 minutes until there is no pink left. Add the fajita seasoning and stir to combine. Set aside.
Into the same hot pan, add the sliced peppers and sliced onion, along with a pinch of sea salt and pepper. Cook the fajita veggies until the onions have softened and have some browning on them, and the peppers are beginning to soften, but still maintain their shape. Set aside when done.
Warm the tortillas in a medium heat skillet.
Serve your ground beef fajitas with sour cream, the seasoned beef, cooked bell peppers and onions, salsa, fresh cilantro, and any other favorite taco toppings!