For the fish sauce: Add 8 quarts water, sugar, sardine scraps, ginger, bay leaves, chile flakes, sardine skeletons, garlic, peppercorns and some salt to a large pot and simmer until reduced by half.
In a medium saucepan, saute the joi choi over medium-high heat for 1 to 2 minutes in the olive oil. Deglaze the pan with a splash of fish sauce and add the parsley. Let reduce for 1 more minute.
For the sardines: Preheat a grill to medium-high heat.
Scale and gut the sardines. Push skewers through the mouth of each fish to the tail in order to make grilling easier. Coat the fish in the olive oil and sprinkle with salt and pepper. Place the fish on the grill and cook for 1 1/2 to 2 minutes on each side. Make sure the eyes are white to determine that the fish are finished.
To serve: Place the greens on a plate and place the grilled sardines on top.
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.