Cemita with Chicken Mole, Avocado, and Pickled Onions

Pickled Red Onions

1. Combine the onions, vinegar, and salt in a small bowl and stir until the salt is dissolved.
2. Cover tightly and refrigerate overnight.
3. The pickled onions keep, tightly covered, up to 1 week in the refrigerator.

Sandwiches

1. Heat the vegetable oil in a heavy skillet over medium-high heat, then add the mole sauce and cook, stirring, until sizzling and a shade darker, about 5 minutes.
2. Stir in the water and bring to a boil, stirring until smooth and combined.
3. Reduce the heat to medium-low, stir in the chicken strips, and cook gently until warmed, about 5 minutes. Remove from heat.
4. Spoon some of the chicken and sauce over the bottom halves of the rolls.
5. Sprinkle the chicken with the toasted sesame seeds.
6. Divide the shredded cheese between the sandwiches, then top with the avocado slices, some pickled red onions, and the top halves of the rolls.
7. Serve immediately.