Preheat the oven to 400ºF. Brush one side of the soft tortillas with olive oil. Place the tortillas oil-side down onto a nonstick baking sheet. Top one-half side with refrigerated walnut meat. Place a second sheet on top to press the tacos down. Bake for about 20 minutes, removing the top baking sheet halfway through. For the Avocado Cream Sauce: Blend 1 avocado, 1 clove garlic, 1/4 cup roughly chopped cilantro, 1/4 cup vegan yogurt, 1 small seeded and chopped jalapeño, and 1 tablespoon fresh lime juice. Add water or olive oil for blending. Season with salt and pepper, and more lime juice to taste.