Place potatoes in pot with salted water, to cover.  Bring to a boil and simmer for 12 to 15 minutes.  Check the potatoes often with a fork.  When they are soft on the outside, but still slightly undercooked in the middle, they are parboiled.  Drain and run under some cold water to stop the cooking process; drain again. Let cool completely.

Prepare the marinade.  Combine the lemon juice, pepper flakes, salt and pepper in a nonreactive (glass, ceramic or stainless steel) bowl and whisk until the salt crystals are dissolved.

Add the lemon zest, garlic, fresh herbs, vinegar and sugar.  Whisk in the olive oil until incorporated.  Use within two hours for maximum freshness.

Carefully slice cooled potatoes into discs measuring at least 3/8" to 1/2" in thickness.  With a basting brush, coat all sides of potatoes, asparagus and chicken. Coat the chicken last to avoid cross contamination.  Allow to marinade for thirty minutes.

 Preheat gas grill to medium high heat.

Place potatoes directly on preheated grill in a single layer.  Once you achieve distinct grill marks on both sides, 2 to 3 minutes per side, transfer them to a sheet pan. Continue grilling with the chicken and asparagus.   Depending on the thickness of the asparagus, it should be done within 3 to 4 minutes.  

Chicken breasts will take about 5-6 minutes per side, depending on thickness.  Be sure to check the chicken breast to be certain it is completely cooked.  If using a meat thermometer, insert the tip into the thickest part of the breast and when the internal temperature reaches 165°F, remove it from the grill. The other option is to cut into the breast and take a peak — the meat should be white, without a rubbery texture, and the juices should run clear. 

All grilled food will be placed on a large sheet pan. Cover loosely with foil. Reheat just before serving for about fifteen minutes in a 300°F oven.

Place grilled food on lettuce lined platter.  Add sliced fresh tomatoes.  Sprinkle with lemon zest and fresh chopped parsley for garnish.