Preheat your oven to 375°F (190°C) and grease a 9×13-inch baking dish.
Slice zucchinis into ¼ inch rounds, sprinkle with salt, and let sit for 15-20 minutes to draw moisture. Blot dry.
In a skillet, heat olive oil over medium-high heat. Cook chopped onion until softened, add ground turkey, and brown until no longer pink. Stir in garlic and Italian herbs.
Mix in the drained diced tomatoes along with black pepper and remaining salt; simmer for five minutes.
Layer half of the zucchini slices in the baking dish, followed by half of the turkey mixture. Repeat layers.
Top with mozzarella cheese. Cover with foil and bake for 25 minutes; remove foil and bake for another 20-25 minutes until bubbly.
Allow to rest for 10-15 minutes before serving to set layers.