Preheat the oven to 375ºF. Position an oven rack to the center position. Line a large baking sheet with parchment paper and set aside.
In a small bowl, mix the oil, tamarind paste, maple syrup, salt, pepper flakes and garlic powder. Set aside 1 1/2 tablespoons of the sauce. You will use it when you toss the roasted vegetables later.
In a medium bowl, mix the tamarind sauce with the vegetable strips. Use your hands to distribute the sauce over the vegetables.
Spread the vegetables over the baking sheet into an even layer. Bake vegetables for 30 minutes.
Toss the apple slaw ingredients together. Set the slaw aside.
When the vegetables are done roasting, drizzle the remaining tamarind sauce on top and mix.
After the roasted vegetables are done, heat up the corn tortillas over a pan. If you want to char the tortillas, heat them directly over a flame.
Assemble the tacos by filling them with a bit of the tamarind-glazed vegetables, apple slaw and pico de gallo. Serve immediately.