Remove the outer leaves of the tomatillos and wash the fruit inside. Cut each in half and place in a small pot. Add the garlic clove and jalapeño. Cover with water and bring to the boil. Lower the flame to medium, cover and cook for 5 minutes or until the tomatillos change from vibrant to olive green.
Combine in a blender the tomatillos (without the cooking water, but save water in case you need it later), the garlic clove, the jalapeño, the onion, the peeled avocado (without the seed), the salt and the cilantro. Blend to a thick, homogeneous consistency.
Warm the tortillas, take two together, one on top of the other, and fill with the chorizo mixture. Then, cover with a spoonful of avocado salsa.
Finish with a squeeze of lime if you'd like!