1. To remove the avocado skin:  Cut into the avocado lengthwise until you hit the pit.  Rotate the knife around the entire pit until you have two halves.  Carefully hit the pit with the knife until it punctures it.  Turn the knife to pop out the pit.  Push a spoon between the avocado and the skin and carve the avocado out of its skin.  Discard the skin.
2. Finely chop the cilantro.  Set aside.
3. Chop the avocado into cubes.  Add to a medium bowl and mash with a fork until smooth.  Add the salt and pepper and cilantro.
4. Slice the chicken breast into approx. 1 inch long x 1 cm wide slices.  Add to avocado mash.  Mix well.
5. Scoop half of the avocado mixture on one slice of the ciabatta.  Repeat this on a second slice.  Top each slice with the remaining two slices.

To Bake Chicken: https://www.thespruceeats.com/how-to-cook-boneless-skinless-chicken-breasts-479540 (for alternate cooking methods)

• Simply preheat the oven to 400 F, drizzle the chicken with olive oil, and sprinkle it with salt and pepper.
• Bake the chicken for 25 to 30 minutes, depending on the thickness of the chicken.
• Remember, the chicken will continue to cook from residual heat after you pull it out of the oven.
• Let the breasts sit for 5 to 10 minutes and then take the internal temperature to ensure it is 165 F.