Make the date BBQ sauce. In a medium saucepan, combine the dates, balsamic vinegar, lime juice, tamari, tomato paste, mustard, onion powder, garlic powder, salt, and pepper. Bring the mixture to a boil and then simmer until dates are soft, about 3 minutes. Transfer mixture to an upright blender and blend on high until smooth, adding water by the tablespoon if necessary. Scrape the date BBQ sauce into a small bowl and set aside. Rinse the blender pitcher.
Make the creamy avocado cilantro sauce. Peel and pit the avocado. Back in the upright blender, combine the avocado, cilantro, garlic, tahini, lime juice, jalapeno, water, salt, and pepper. Blend the mixture on high until completely smooth, adding more water by the tablespoon if necessary. Scrape the avocado cilantro sauce into a separate container and refrigerate until ready to use.
Make the filling. Heat the oil in a large skillet over medium heat. Add the shallot to the skillet and saute until slightly softened and translucent, about 3 minutes. Add the grated sweet potatoes and stir. Season the filling with salt and pepper. Keep stirring until sweet potato shreds start softening and collapsing into each other, about 4 minutes. Add a splash of water if you notice some sticking.
Once sweet potato shreds are soft, add the date BBQ sauce to the skillet and stir to combine. The filling should look quite saucy at this point. If it seems dry, add another splash of water. Keep stirring until the filling is saucy, sticking to the sweet potatoes, and piping hot, about 3-4 minutes.
Divide the sweet potato filling among the warm tortillas. Top each sticky sweet potato taco with shredded cabbage and plenty of the avocado cilantro sauce. Serve tacos with extra lime wedges if you like.