Preheat the oven to 375 degrees Fahrenheit.

Lay 2 of the flour tortillas into the bottom of a 9x13 baking dish. Trim edges to fit, using remaining tortillas as templates.

Spray a 9x13 baking dish with nonstick spray and set aside.

In a medium saucepan, cook ground beef, onion, and garlic over medium-high heat until beef is browned and cooked through. Drain excess fat.

Stir in taco seasoning and water; cook for 2-3 minutes until sauce thickens. Remove from heat.

Spread half of the cooked meat mixture over the first layer of tortillas.

Spread half of the salsa over the meat layer.

Sprinkle half of the black beans and cheese over the salsa.

Add a layer of 2 tortillas on top, then repeat layers: meat, salsa, beans, cheese.

Cover with foil and bake for 20-25 minutes. Garnish with cilantro, serve with sour cream and pico de gallo if desired.