Preheat oven to 400 degrees F and line one large baking sheet with parchment paper.
Cut the potatoes into bite-sized chunks. In a large mixing bowl, combine the potatoes, black pepper, onion powder, garlic powder, chili powder, cumin, nutritional yeast, and flour. Toss and mix well. Pour in the tamari, vinegar, oil and continue to mix and toss until all the pieces are coated thoroughly.
Spread the potatoes in an even layer on the baking sheet and cook for 25 minutes. Remove and give one piece a taste. Season with sea salt as needed. Flip with a thin spatula and shake the potatoes into an even layer. Bake for an additional 10 to 15 minutes, to get them crispy.
While the potatoes are baking, whip up the aioli. First, blend the lime juice, cilantro, jalapeño (if using), sea salt, and nutritional yeast in a small blender. Blend for a minute or two until you are left with a bright green liquid. Transfer to a small mixing bowl and add the mayo. Using a whisk, mix until smooth. Transfer to a squeeze bottle or tightly cover and keep in the fridge.
Assemble the tacos by placing on some lettuce, potatoes, sliced red onion, sliced jalapeño, fresh cilantro on a warm, soft tortilla. Drizzle with the aioli and enjoy.