How to Make It
In a medium bowl, combine the ancho chile powder with the ground pepper, allspice, cloves and a heaping 1/4 teaspoon of salt. Add the top sirloin and 2 teaspoons of the lime juice and toss to coat the meat.
Preheat the oven to 300°. In a large skillet, heat 1 1/2 tablespoons of oil. Add the onion and poblano and cook over moderately high heat until the onion begins to brown. Add the meat and stir until just barely cooked through, about 2 1/2 minutes. Add the cilantro and season with salt.
In a bowl, toss the avocados with the remaining 2 teaspoons of lime juice.
Heat a large skillet or griddle. Lightly brush a tortilla on both sides with oil and lay it in the skillet. Cook over moderate heat for 45 seconds, then flip the tortilla and sprinkle 1/4 cup of the mozzarella over half of it. Top the cheese with a quarter of the sirloin cubes and avocado slices. Sprinkle with another 1/4 cup of cheese. Fold the tortilla over the filling and press down with a spatula to form a taco. Continue cooking for 30 seconds, then turn and cook until the underside is golden, 1 minute longer. Keep the pirata warm in the oven while you repeat with the remaining tortillas and fillings. Serve warm, with salsa.