Using a food processor, puree the jam, 1 tablespoon soy sauce and 1 garlic clove. Transfer to a resealable freezer bag, add the shrimp and refrigerate for 30 minutes.
Using the food processor, puree the remaining garlic clove, remaining 3 tablespoons soy sauce, the peanut butter, brown sugar and lemon juice. With the machine on, slowly pour in 1/3 cup water. Add hot sauce to taste.
Preheat a grill to medium-high. Thread 6 shrimp onto each of 4 skewers. Place on the grill, cover and cook, turning once, until firm and charred, about 4 minutes. Transfer to a platter and top with the scallions. Serve with the peanut dipping sauce.