Pat chicken thighs bone-dry. Dice into 1/2-inch pieces and toss in a bowl with avocado oil, salt, paprika, and cumin until evenly coated.

Finely chop the white onion and fresh cilantro. Set aside for assembly.

Heat a cast iron skillet over medium-high heat. Add chicken in a single layer and cook undisturbed for 4 minutes to achieve dark sear marks. Flip and cook for another 3 minutes until internal temp is 165°F (74°C).

Place corn tortillas over an open gas flame or in a dry hot skillet for 20 seconds per side until they show charred edges and toasted brown spots.

Place three charred tortillas in a taco holder. Fill each with a generous portion of the seared chicken. Top with onions, cilantro, and a light sprinkling of cotija cheese.

Tuck a fresh lime wedge beside the tacos and serve immediately while hot and glistening.