Mix lemongrass, lime juice, sugar, soy sauce and garlic in large bowl. Add pork; toss to coat with marinade. Let stand 30 minutes to 1 hour.
Preheat broiler. Thread 3 pork strips on each skewer. Grill until cooked through, about 3 minutes per side. Pour sauce into bowl; set in center of platter. Sprinkle with green onion. Surround with pork skewers and serve.
In a blender blend together the peanut butter, the garlic, the lime juice, the soy sauce, the sugar, ginger, the cayenne, the water, and salt and pepper to taste until the mixture smooth and transfer the sauce to a bowl. The sauce may be made 2 days in advance and kept covered and chilled.
Yield: 1 cup