Cook the lentils according to the instructions. Drain and set aside. In a medium pan, roast the walnuts without oil for about 2 minutes or until they're lightly golden. Put the walnuts and the cooked lentils in a food processor and process until chopped. Make sure to leave some texture!
In a medium pan, heat the olive oil over medium heat and sautée the onions for about 3 minutes. Then add the lentil walnut mixture and stir in the tomato paste. Cook for 2 minutes. Add the diced tomatoes and the spices (paprika powder, cumin, oregano) and season with salt and pepper.
Preheat the oven to 385 °F and bake the pizza dough for about 10 minutes until it's golden and crispy.
After baking, evenly spread the pizza with vegan sour cream. Add a layer of the vegan lentil walnut meat and top with avocado, tomatoes, lettuce, corn, kidney beans, and vegan cheese. Sprinkle with red pepper flakes. Enjoy!