Preheat oven to 375 degrees F (190 degrees C). Spray a 9x13x2-inch casserole dish with cooking spray. Take 1 cup of cooking sauce and spread it evenly on the bottom of dish. Set aside.
For enchilada filling: In large non-stick skillet sprayed with cooking spray, saute 1 cup diced onions and garlic until onions are translucent, about 5 minutes.
Add in the ground turkey and cook until browned. Next add in ground cumin, salt, chopped green chilies, cayenne (if using), salt, zucchini and 1/4 cup cooking sauce.
Mix well and take off heat.
To assemble enchiladas: Take one flour tortilla and, in the center, put about 1/3 to 1/2 cup of the turkey-zucchini mixture down the middle in a strip.
Place 2 tablespoons Monterey Jack cheese on top of turkey mixture and roll up.
Place in prepared casserole dish with seam side down. Repeat with remaining tortillas, placing them side by side.
Pour the second jar of cooking sauce on top of the enchiladas, coating them evenly with the sauce.
Sprinkle with remaining cheese. Cover with foil.
Bake for 30 to 35 minutes in the preheated oven, or until the sauce is bubbly and the enchiladas are warmed through.
Garnish with chopped onion, cilantro, and sour cream, if desired.
