In a large skillet, heat 1 tablespoon of oil over medium heat. Add finely chopped onion and sauté for 2-3 minutes, or until translucent. Incorporate 1 pound of ground beef into the skillet, cooking it for 4-5 minutes until nicely browned. Mix in 2 tablespoons of tomato paste and taco seasoning, adding a few tablespoons of water for moisture. Cook for another 3-4 minutes until slightly saucy.

Grab a tortilla and lay it flat. Sprinkle 1½ to 2 tablespoons of mozzarella cheese on the top half, followed by a portion of your beef mixture. Top with more cheese and fold to seal. Repeat for all tortillas and place on a baking sheet.

In the same skillet, heat 3-4 tablespoons of oil over medium-high heat. Add assembled tacos in batches, frying for about 1 minute on each side until golden-brown. Transfer to a wire rack to drain excess oil.

Arrange fried tacos on a serving platter. Garnish with fresh cilantro and serve with toppings like avocado slices or sour cream.