In a large bowl combine the olive oil, ancho, smoked paprika, white pepper, salt, coriander, cayenne, black pepper and red pepper flakes. Add the chicken thighs, toss to coat and set aside.
Heat a large skillet over medium-high heat. Place the chicken thighs into the skillet and cook until chicken is crisp and seared, about 7 minutes. Flip and continue to cook until the chicken is cooked through, another 6 to 8 minutes.
Transfer the cooked chicken to cutting board and allow to rest for a few minutes, until chicken is cool enough to handle. Chop into bite-sized pieces, about 1/2-inch. Set aside.
Working with one tortilla at a time, spread 1/4 cup of refried beans over tortilla up to 1/2-inch from the edge. Top with 1/4 of the chopped chicken, 1/4 chopped avocado, 1/4 cup sliced tomatoes and 2 tablespoons of the scallions.
Fold the left and right sides in 1/3 of the way, then take the bottom (side closest to your body) and roll up. Repeat with the remaining tortillas and ingredients.