Preheat the oven to 400F. Lightly grease a large baking tray.
In a large, shallow bowl, whisk together the panko breadcrumbs, chili powder, salt, paprika, cumin, garlic powder, and cayenne (if using). Then, stir in the oil until incorporated.
In another large, shallow bowl, whisk together the milk, flour, and lime juice until smooth.
From left to right, line up the tofu cubes, milk batter, breadcrumb mixture, and baking tray. Place a handful of the tofu cubes into the batter, toss to coat, use a slotted spoon to shake off excess batter, and transfer to the breadcrumb mixture. Toss to coat and transfer to the prepared baking tray. Repeat with the remaining tofu.
If extra crispiness is desired, spray*** the tofu cubes with a bit more oil.
Bake for 35 to 40 minutes, or until crisp and golden brown, tossing a few times throughout baking. Remove from the oven and let cool slightly.
Meanwhile, prepare the Cilantro-Jalapeño Ranch (recipe below) and gather/prepare the toppings and garnishes.
Warm the tortillas just before assembling. Heat them, one at a time, in a small skillet over medium heat for 20–30 seconds per side.