In a large bowl or resealable zip-top bag, combine the lamb and ½ cup This Little Goat Went to Hong Kong sauce. Toss until well coated. Set aside to marinate for at least 15 minutes, or refrigerated up to overnight Meanwhile, in a small bowl whisk together the mayonnaise, 2 Tbsp Hong Kong sauce, lemon juice, 1 Tbsp each chopped scallions and cilantro and a pinch of kosher salt. Set aside. Heat a grill or grill-pan to medium-high heat. Skewer the marinated lamb and pineapple onto wooden or metal skewers, alternating between each and stopping at least 2-inches before the end of the skewer. Sprinkle with a pinch of kosher salt. Grill until the meat is lightly charred on both sides and cooked through, about 4 minutes per side. (If the meat is getting too dark before it's cooked through, move to indirect heat or lower the heat and continue grilling until the lamb is cooked through). Remove from the grill and drizzle with spiced Hong Kong mayonnaise. Top with reserved chopped cilantro and scallions.