Cover the chicken breasts with plastic wrap and pound until each pieces is about a ¾ of an inch thick. Place the flour and salt in a shallow dish and gently toss each chicken breast in the dish to coat. Melt the butter in a large skillet over medium high heat; add the chicken and sauté for 3-5 minutes on each side, until golden brown, sprinkling each side with the lemon pepper directly in the pan.
When the chicken is cooked through, transfer to a plate. Add the lemon slices and chopped asparagus to the pan. Make sure the lemon slices are on the bottom so that they caramelize and pick up the browned bits left in the pan from the chicken and butter.
When the asparagus is done and the lemons are golden brown, add the chicken back to the pan and rearrange everything (lemons on top) so it looks nice for serving.