Make the chipotle pineapple sauce. In a blender or food processor combine the garlic, chili powder, paprika, chipotle chilies, 1/3 cup water, vinegar, 1 cup of the pineapple chunks, and a pinch of salt. Blend until completely smooth. Stir in the sesame seed. Heat the olive oil in a large skillet over medium heat. When the oil shimmers, add the cremini mushrooms, onions, and a pinch each of salt and pepper. Cook for 5 minutes, until the mushrooms begin crisping on the edges. Add the shiitake mushrooms, and continue to cook another 5 minutes. Reduce the heat to low, stir in about 1/2 of chipotle pineapple sauce and the remaining 1 cup of pineapple chunks. Simmer for 5-8 minutes or until the sauce has reduced and coats the mushrooms, there will still be sauce left in the pan. Remove from the heat and stir in the cilantro.To make the special sauce. Combine all ingredients in a bowl, adding 1-2 tablespoons water if needed to thin the sauce. Taste and season with salt.Stuff the mashed avocado (if using), the mushrooms, and pineapple into the warmed tortillas. Top with additional chipotle pineapple sauce, special sauce, cilantro, and cheese. Enjoy!