Melt the butter in a medium skillet over low to medium heat. Add ground beef and cook for 5 minutes, breaking it up with a wooden spoon. Add salt and garlic and cook for another 5 minutes, stirring occasionally. Add tomato sauce and simmer until the meat is thoroughly cooked, about 10 minutes.
Heat oil in a small skillet over medium heat. When hot, place a tortilla in the skillet and cook for 1 minute. Using a fork, fold the tortilla in half so that it makes the shape of a taco. Turn it over, so the other side becomes crunchy. Remove from oil and drain on a plate layered with paper towel. Cook remaining tortillas in the same manner, adding oil as needed.
Place tomato, avocado, lettuce, sour cream and cheese in small bowls.
Place 1 to 2 tablespoons of beef mixture in each taco and put them on a serving plate.
Fill tacos as desired, sprinkle with Pico Pica and enjoy immediately!