Preheat the oven to 375°F.

Lay 2 of the flour tortillas into the bottom of a 9x13 baking dish. Using a sharp knife, or a pizza cutter to trim the excess tortilla edges. Use the 2 trimmed tortillas as a pattern to trim the remaining 2 tortillas for the 2nd layer of the lasagna.

Spray a 9x13 baking dish with nonstick spray. Set it aside.

Using a 3 - 4 quart saucepan over medium-high heat, add the ground beef, onion and minced garlic. Cook the ground beef until it is cooked through, and no longer pink. Reduce the heat to medium-low.

Using a small mixing bowl, whisk together the taco seasoning and 1 cup of water. Pour over the cooked ground beef. Cook for another 2-3 minutes, or until the meat mixture begins to thicken. Stir often. Remove from the heat.

Arrange 2 of the trimmed flour tortillas in the bottom of the prepared baking dish.

Evenly spread 0.5 of the meat mixture on top of the tortillas.

Evenly spread 0.5 of the salsa over the meat mixture.

Evenly sprinkle 0.5 of the black beans over the salsa.

Evenly sprinkle 0.5 of the shredded cheese over the beans.

Arrange the last 2 tortillas over the shredded cheese, and repeat the final layers of ingredients (meat mixture, salsa, black beans, and shredded cheese).

Bake for 20 - 25 minutes. Remove from the oven, and garnish with the chopped cilantro. Top with sour cream and pico de gallo if desired. Serve while hot.