Step 1Remove the stems and seeds from the chiles and place the peppers in a glass bowl. Pour boiling water over to cover by 3 inches and let them soak until very soft, about 30 minutes.
Step 2Drain the peppers and place them in a blender with the garlic and oregano. Strain the soaking water and add 1 1/2 cups to the blender. Puree until smooth. Strain the mixture through a sieve into a clean, shallow pie plate; season with salt and set aside.
Step 1Heat the olive oil in a large, heavy skillet over medium heat. Add the garlic, onion and pepper. Stir in about one-half teaspoon coarse sea salt. Cook, stirring often, until soft, about 8 to 10 minutes. Add the eggplant and zucchini and the remaining one-half-teaspoon salt. Cook until soft, 10 to 15 minutes longer. Stir in the oregano and cumin and remove from the heat.
Step 2Heat the oven to 350 degrees. Oil a 13-by-9-inch baking dish. Coat the bottom with about 2 tablespoons sauce. Set aside.
Step 3Heat about 1 inch oil in 9-inch nonstick skillet over medium heat. Reduce the heat to low. With tongs, sweep 1 tortilla through the hot oil just long enough to coat and soften (about 10 seconds). Lift it out with tongs and drain off excess oil. Dredge it through the chile sauce to coat, then lay it into the prepared pan so that half the tortilla extends up the side. Spoon about 2 tablespoons vegetable mixture down the center, then top with about 2 tablespoons cheese. Roll up to enclose the filling and turn the seam side down. Repeat this process with the remaining tortillas and filling. Spoon any remaining sauce evenly over the assembled enchiladas. Sprinkle remaining cheese on top.
Step 4Bake until the tortillas are soft and the cheese is melted, 20 to 25 minutes; do not over-bake. Serve hot, garnished with chopped lettuce and radishes and a drizzle of crema, if desired.