Line a large baking sheet with parchment paper and arrange the tortillas. Brush with olive oil and sprinkle salt.
Bake the tortillas for 10 minutes or until golden brown. They will get crunchier as they cool down.
Prepare the carne asada:
Season the skirt steak generously with salt and pepper. Let it rest at room temperature for 20-30 minutes.
Preheat a cast iron over medium high heat until smoking hot. Grill the steak, about 2-3 minutes per side for rare or until the desired temperature. Transfer it to a cutting board and let it rest for at least 5 minutes. Then, slice across the grain.
Pistachio Chimichurri:
Combine the parsley, garlic, pistachios, red wine, salt, freshly ground pepper and 1/4 cup olive
oil in a food processor. Pulse until well blended but still coarse. Remove to a small bowl and stir
in the remaining olive oil and red pepper flakes. You can make it ahead and store in the fridge overnight.
Assembling the tostadas:
Top each tostada with carne asada, pistachio chimichurri sauce and desired toppings. You can also just serve the toppings in individual bowls and let guests prepare their own tostadas.