Heat vegetable oil to medium heat in a large sauté pan. Add onion and sweat for 2-3 minutes or until the onion is tender and translucent.
Add the garlic cloves and cook for 1 minute.
Add the zucchini and cook until tender, about 3-4 minutes. Add the black beans and mix well. Let cook for 1 minute more. Season with salt and pepper.
To make the sauce: heat a griddle, comal, or cast iron pan to medium-high heat. Toast chiles on each side until lightly toasted, about 30 seconds on each side. Remove from pan and set aside.
Add the almonds to the pan and toast until golden, about 2 minutes. Remove from pan and set aside.
Toast the onion, and the garlic until slightly charred, about 4 minutes on each side.
Place the almonds, onion, garlic, and chiles in the blender. Add the warm vegetable stock and 2 tsp. of vinegar. Process until smooth. Season with salt and pepper. Sauce should be thick and creamy.