Preheat oven to 350°F.
Slice zucchini in half lengthwise and scoop out the centers to create a boat.
In a medium skillet, brown ground beef and onion together until beef is browned and crumbly. Add garlic, smoked paprika, cumin and salt to taste. Stir until combined.
In a 13x9-inch baking dish, add zucchini boats flesh side facing up. Spoon ground beef mixture evenly into each zucchini half. Pour enchilada sauce over filled zucchini and sprinkle with shredded cheddar cheese.
Cover with foil and bake 30 minutes. Uncover and bake another 10 minutes or until zucchini are tender.
Garnish with fresh cilantro, if desired.