Drain and rinse the canned jackfruit thoroughly. Trim off the hard core of each piece and discard, then use your fingers or a fork to shred the remaining jackfruit into a pulled-meat texture.
Finely chop the seitan into small crumbles to mimic the texture of ground meat.
Heat the olive oil in a large non-stick skillet over medium heat. Add the shredded jackfruit and seitan crumbles, sautéing for 5-7 minutes until the edges begin to brown and crisp.
Stir in the chili powder, cumin, smoked paprika, garlic powder, sea salt, and black pepper. Add the black beans and 2 tablespoons of water to the pan, stirring to coat everything in the spices. Simmer for 3-4 minutes until the water has evaporated and the flavors are well-combined.
While the filling simmers, prepare the crema by mashing the avocado with the fresh lime juice in a small bowl until completely smooth and creamy.
Warm the corn tortillas in a dry skillet or over an open flame for 30 seconds per side until pliable.
Divide the jackfruit and bean mixture evenly between the tortillas. Top each taco with a dollop of the avocado crema and a sprinkle of fresh cilantro.