Place cauliflower in a microwave-safe bowl and add 1 tablespoon water. Cook in the microwave on high power to desired tenderness, about 2 minutes.
Heat olive oil in a pot over medium heat. Add beans, corn, and onion. Cook and stir to desired tenderness, about 3 minutes. Mix in onion powder, garlic powder, Cajun seasoning, paprika, and cumin. Remove from heat.
Stir taco sauce, flaxseed meal, nutritional yeast, and tomato into the pot with the bean mixture. Fill tortilla with filling and add cooked cauliflower. Top with leafy greens.