For the Tostones

1. Optional: Soak the green plantains in a bowl of cold water for 20-30 minutes to make them a bit easier to peel.
2. Cut a slit through the plantain skin lengthwise to peel, taking care not to cut into the fruit. Slice peeled plantains crosswise, about an inch thick.
3. Add plantains to a medium pot of cool water, add the salt, and bring to a boil. Boil 10-12 minutes, until fork tender. Drain and rinse with cold water, then heat a non-stock skillet over medium-high heat. Some people skip boiling and double-fry them (once to soften and once after smashing), but we’re going for less oil.
4. Generously brush the pan with oil and add several plantain slices, but leave plenty of room (we’re going to smash them down). Brush the bottom of a bottom of a mug, mason jar, etc., with oil and use it to smash the plantains down in the pan. Not too thin or they’ll crumble. Cook to a golden brown, adjusting heat as needed, then flip and cook other side. These can also be smashed and deep fried, but we prefer to use minimal oil. You do you, though. 
5. Place browned plantains on a plate lined with paper towel to drain off excess oil and sprinkle with a pinch of salt and ground black pepper, if desired. Tip: Prep and boil the plantains when starting the taco mixture and finish them off while the taco mixture is cooking down so everything is ready at once. 

For the Tacos

1. In a small bowl, combine the chili powder, cumin, ground black pepper, onion powder, paprika, Mexican oregano, garlic powder, and salt. Set aside. 
2. Prep all vegetables, then set oven rack to one down from top position and set oven to broil high. Line a rimmed baking sheet with foil and coat with a teaspoon of the avocado oil. Place the tomatoes on the prepared sheet. If you don’t have a gas stove, slice the bell peppers lengthwise, remove seeds, and place skin side up on the sheet with the tomatoes. Broil until charred to preference, 10-15 minutes (the peppers will char faster than the tomatoes, so watch closely). If you do have a gas stove, char directly over the flame on a burner, turning as needed with tongs, then deseed and dice once cool enough to handle. 
3. Heat a large sauté pan over medium-high heat. Once the pan is very hot, add the remaining 2 teaspoons of avocado oil and add the onions and mushrooms. We want to get a quick sear on one side of the mushrooms to bring out the flavor as well as caramelize the onions a bit. once seared, reduce heat to medium and stir the mushroom and onion mixture until they begin do soften and break down. Scrape the bottom of the pan as needed. 
4. Add jalapeno, eggplant and zucchini and stir well. The eggplant and zucchini will release quite a bit of liquid, which will deglaze the bottom of the pan as the vegetables cook down. Cook until softened and reduced by about half (5-10 minutes), then add tomatoes and peppers and toss to combine. 
5. Sprinkle with spice mixture and walnuts, tossing to coat evenly and pour 1/4 cup water over the pan. Stir to combine completely, then cook off excess liquid for about another 5-7 minutes. 
6. Divide the plantain slices between six plates with taco mixture on the side or on top. Garnish with fresh cilantro and serve immediately with lime wedges.