Preheat the oven to 350°F (175°C).
Trim the zucchini ends and, using a mandoline or sharp knife, slice the zucchini into thin slices about 1/8 inch thick.
Arrange the zucchini slices in a single layer (it's okay if they overlap slightly) on two baking sheets; sprinkle evenly with 1 tablespoon salt.
Bake the salted zucchini slices for 15–20 minutes until they just begin to brown to remove excess moisture.
Transfer the baked zucchini to a plate or baking pan lined with paper towels; cover with more paper towels and gently press to absorb and remove as much moisture as possible. Set aside.
While the zucchini bakes, heat the olive oil in a large skillet over medium-high heat. Add the ground turkey, diced onion, the diced garlic (1 Tbsp + 2 tsp total), taco seasoning (1 Tbsp + 1 tsp total), and a pinch of pepper.
Cook, stirring occasionally, until the onion is soft and the turkey is browned, about 10–12 minutes. Remove from heat and set aside.
In a medium bowl, combine the tomato sauce and salsa and stir until blended.
In another bowl, beat the ricotta with the egg and a pinch of pepper until smooth.
Spray a 9×13-inch baking dish with cooking spray. Spread half of the tomato sauce mixture evenly over the bottom of the dish.
Top the sauce with half of the cooked turkey, then arrange half of the zucchini slices in a single layer over the turkey. Spread half of the ricotta mixture over the zucchini.
Sprinkle half the chopped cilantro and half the grated Mexican cheese over the ricotta layer.
Repeat the layers: remaining sauce, remaining turkey, remaining zucchini, remaining ricotta, remaining cilantro, and remaining cheese.
Sprinkle the chopped red bell pepper over the top layer of cheese.
Increase the oven temperature to 375°F (190°C) and cover the baking dish with aluminum foil.
Bake covered for 45 minutes, then uncover and bake for an additional 10 minutes.
Turn the broiler to high and broil the lasagna 2–3 minutes until the top is golden brown and bubbly; watch closely to avoid burning.
Remove from the oven and let rest 5–10 minutes. Garnish with additional cilantro if desired and serve hot.