Step 3: Place the walnut meat on one-half side of the tortillas. Fold the other sides over to cover. Place a second baking sheet on top of the folded tacos for the first 5 minutes of baking. Remove the upper baking sheet, and bake until the desired crispiness.
Step 4: For the optional avocado crema: Blend the avocado, jalapeño, cilantro, garlic, yogurt, lime juice, olive oil or water in a food processor until smooth.