Preheat oven to 400 degrees F. Line a baking sheet with foil, and then set aside.
Place a large skillet over medium heat. Add vegetable oil. Once the oil is hot, add onions and garlic and cook for 2 minutes, stirring often.
Add ground beef to skillet. Use a spatula or wooden spoon to break up the meat. Cook until no longer pink, about 5 minutes. Drain any excess grease.
Add salsa, chili powder, salt, and pepper to skillet. Stir until evenly mixed with ground beef. Reduce heat to low and simmer for 10 minutes.
Top a tortilla with 1/4 cup of the beef mixture in a straight line towards one side of the tortilla (see image in post). Sprinkle with some cheese. Roll up the tortilla and place on prepared baking sheet seam side down. Repeat with remaining ingredients.
Brush a little oil over the top of each taquito. Bake for 8 to 12 minutes or until browned and crispy.
Carefully remove from oven. Serve warm with sour cream, guacamole, and more salsa if desired.
You can also spray the tops for the taquitos with non-sticking cooking spray if you prefer. This light coating of oil helps them brown up and get nice and crispy quickly.