Preheat oven to 400 F. Remove the stem and halve each zucchini lengthwise. Sprinkle all the halves with 1/2 teaspoon salt and 1/2 teaspoon pepper. Place the zucchini on a baking sheet and bake until tender, 10 to 15 minutes. Set aside to cool.
In a small bowl combine the cauliflower, 1/2 cup cheese and the remaining salt and pepper. Mash until all ingredients are fully incorporated. Using a spoon scoop out flesh of each zucchini leaving a 1/4 to 1/8-inch border.
Fill each zucchini half with cauliflower mash. Top each with a sprinkle of chorizo and the remaining cheese.
Bake until the cheese is melted and golden brown, about 10 minutes. Sprinkle with fresh parsley.