Make the slaw: In a medium bowl, toss 1 cup shredded cabbage with the juice of 1 small lime and 1/2 teaspoon kosher salt; cover and refrigerate until assembly.
Prepare the chicken seasoning: Combine the zest of 1 small lime with 2 tablespoons taco seasoning in a small bowl.
Season the chicken: Sprinkle the lime–taco seasoning mixture over both sides of 1 pound boneless skinless chicken and rub to coat.
Pan-fry the chicken: Heat 1/2 tablespoon olive oil in a non-stick skillet over medium-high heat. Cook the chicken 4–5 minutes per side until golden and the internal temperature reaches 165°F (74°C).
Rest and slice: Transfer chicken to a plate and let rest 5–10 minutes. Slice into 1/4-inch pieces, squeeze the remaining lime juice over the slices, and gently toss.
Prepare the rolls: Halve each roll horizontally. Spread mayonnaise on the top halves and spread refried beans on the bottom halves.
Assemble the tortas: Sprinkle 1/2 cup crumbled queso fresco over the beans, top with sliced chicken, then add tomato slices, thinly sliced onion, the seasoned cabbage slaw, and sliced avocado.
Serve immediately: Close the sandwiches and serve right away.