Preheat the oven to 350°F.
In a small saucepan, heat the water, sugar, vinegar, and salt. Place the onion and carrots in a heatproof bowl, cover with the vinegar mixture and cool to room temperature.
On one baking sheet, toss the red onion and poblanos with 2 tablespoons oil, oregano, salt and pepper. Roast for 15 minutes.
On a second baking sheet, toss the zucchini with 1 tablespoon oil and a pinch of salt and pepper. Roast for 15 minutes.
On a third baking sheet, toss the roma tomatoes, jalapeños, and yellow onion with the canola oil. Roast for 10-15 minutes, until browned. Transfer to a blender, along with the remaining roasted salsa ingredients. Blend until smooth and season to taste.
In a large bowl, combine the roasted onions, poblanos, zucchini and goat cheese.
Lay the flour tortillas on a work surface and fill with enchilada filling. Roll to close and arrange in a large baking dish, seam side down. Cover with half of the roasted salsa and sprinkle with Oaxaca cheese. Bake for 20 minutes, until the cheese is melted and bubbly.
Meanwhile, make the quinoa by heating the oil in a small saucepan over medium heat. Add the tomato paste and achiote paste and cook until fragrant, 1-2 minutes. Add the quinoa and toast, stirring, fro 3 minutes. Add 2 cups of water, bring to a simmer, reduce heat to low, cover and cook until the grains are tender, about 12 minutes. Fluff the quinoa with a fork, then stir in the black beans.
Serve the enchiladas with remaining salsa, pickled carrots and onions, and quinoa.