Breaded Chicken Sandwiches with Sesame Rolls (Cemita Poblana de Milanesa)

Using a sharp knife, carefully slice the chicken breasts in half lengthwise. Then, one at a time, sandwich the chicken pieces between two pieces of plastic wrap, and pound with a meat pounder to 1/4-inch thickness.
In a shallow mixing bowl, combine the flour, chili powder, paprika, salt, and pepper. In a separate bowl, beat the eggs. Place the breadcrumbs in a third bowl. Season the chicken pieces lightly with salt. Dip each piece first into the flour mixture, turning to coat. Let any excess flour fall away, then transfer the chicken to the beaten eggs. Let any excess egg drip off, then transfer the chicken to the breadcrumbs and press to coat both sides evenly. Transfer to a platter.
Set a large paper towel–lined plate next to the stove. Heat a large skillet or griddle over medium-high heat and add 2 to 3 tablespoons oil. When the oil is hot, add 1 or 2 pieces of chicken at a time and cook, turning once, until crispy and browned on both sides and just cooked through, about 8 minutes total. Transfer to the prepared plate and repeat with the remaining chicken breasts, adding more oil as needed for each batch.
To assemble the sandwiches, preheat the oven to 350°F. Cut the rolls in half and place them cut side up on a baking sheet; bake until lightly toasted, about 5 minutes. Cut the avocados into quarters and thinly slice. Spread some of the Salsa de Morita onto the bottom of each roll, then top with a piece of chicken, a few slices of onion, the sliced avocado, romaine, and cheese. Spread the mayonnaise and refried beans on the top half of the rolls and place on top of the sandwiches.