Place the walnuts in a food processor and mix to give a coarse crumb. Repeat with the mushrooms and mix into the walnuts.
Heat the oil in a large saucepan and fry the walnut mixture and garlic for 5 minutes. Add the spices and cook for 1 minute.
Stir in the tomatoes, tomato puree and both beans and cook gently for 10 minutes, stirring occasionally. Season and stir in the coriander.
Spread the chilli mince down the centre of the tortilla wraps, top with the rice and sliced avocado, fold over the side and wrap up. Cut each in half to serve.