Heat the vegetable oil in a large pot over medium-high heat. Add the flour and cook, stirring, until golden, about 3 minutes. Add the onion, bell pepper, celery, garlic, 3 tablespoons water and 1/4 teaspoon each salt and pepper. Reduce the heat to medium, cover and cook, stirring occasionally, until the vegetables soften, about 8 minutes.
Add the soy sauce and paprika and cook, stirring, 30 seconds. Stir in the vegetable broth, scraping up any browned bits from the bottom of the pot, then cover and bring to a boil.
Add the greens and black-eyed peas to the pot. Reduce the heat, cover and simmer, stirring occasionally, until tender, about 15 minutes. Season with salt and pepper. Serve with the rice, if desired.