Heat oil in a large pan over medium heat. Crumble tofu into roughly 1-inch pieces and add to the pan. Cook, stirring occasionally, for 5 minutes. Add canned tomatoes and cook until excess liquid has evaporated, 5 to 10 minutes. Add bell pepper and onion and cook until onion is translucent, about 5 minutes. Add garlic, nutritional yeast, soy sauce, red pepper flakes, paprika, turmeric, and salt. Cook and stir for 2 minutes more.
Spread mayonnaise over sandwich buns and top with tofu mixture, spinach, and avocado.