Dice the chicken breast into bite-sized pieces and toss in a bowl with cumin, smoked paprika, sea salt, and black pepper until evenly coated.
In a separate small bowl, combine the diced Roma tomatoes, finely diced red onion, chopped cilantro, and half of the lime juice to create the fresh salsa.
Heat the avocado oil in a non-stick skillet over medium-high heat. Add the chicken and sear for 6-8 minutes, stirring occasionally, until golden brown and cooked through.
While the chicken cooks, toss the shredded cabbage with the remaining lime juice in a small bowl to create a light, crunchy slaw.
Warm the corn tortillas in a dry pan or directly over a low gas flame for 30 seconds per side until soft and pliable.
Assemble the tacos by dividing the cabbage slaw between the tortillas, topping with the seared chicken, fresh salsa, and thin slices of avocado.