Cook black bean spaghetti according to directions until al dente.
Meanwhile, heat a sauté pan on medium heat. Once heated, lightly coat with non-stick cooking spray and add celery and bell pepper. Cook until slightly translucent, about 5 minutes, stirring frequently to prevent burning.
Add zucchini, Italian seasoning and garlic. Cook until zucchini is tender, about another 5 minutes, continuing to stir frequently.
Reduce heat to low, add marinara sauce, and cook for an additional 2 minutes or until sauce is heated thoroughly.
Divide black bean spaghetti and sauce into two servings (optionally top with a sprinkle of Parmesan or vegan cheese) and enjoy!