Moroccan Harissa Roast Cauliflower

Name: Moroccan Harissa Roast Cauliflower
Ingredients: 5 dried New Mexico chiles (about 1 ounce); 4 dried guajillo chiles (about 1 ounce); 2 cups boiling water; 1/4 teaspoon whole coriander seeds; 1/4 teaspoon whole cumin seeds; 2 tablespoons vegetable oil, plus more for roasting; 3 cloves garlic, roughly chopped; Juice of 1/2 lemon (about 1 tablespoon); Kosher salt and freshly ground pepper; 1 large head cauliflower, cut into 2-inch florets (about 8 cups); 1/4 cup lightly packed fresh cilantro leaves