Preheat the oven to 350°F (180°C) and grease a 9 x 13-inch (22x33 cm) baking dish with cooking spray.
Heat the olive oil in a medium pan over medium-high heat. Add the green pepper and onion and sauté until soft and the onion is translucent, about 6 minutes.
Add the ground turkey and break up with a wooden spoon. Cook for another 4 minutes, or until it is no longer pink. Add the water and taco seasoning and bring to a boil. Reduce the heat to medium-low and simmer for 2 minutes.
Stir in the black beans, corn and fire-roasted tomatoes. Continue to simmer, uncovered, for 10 minutes, until thickened, then remove the pan from the heat.
Place 2 tortillas in the prepared baking dish. Spread half of the refried beans and half of the turkey mixture over the tortillas and sprinkle with 1 cup cheese. Repeat to make another layer, then top with remaining 2 tortillas and 1 cup cheese.
Cover the baking dish with foil and bake for 25–30 minutes, or until the lasagna is warmed through and the cheese is melted and bubbling. Broil on high for 2–3 minutes, until dark golden brown and bubbling.