Add this spicy shrimp appetizer to your party or potluck menu. It's the perfect make-ahead recipe for any gathering.
In a small bowl, soak red pepper flakes in vinegar for 30 minutes.
Meanwhile, bring 3 quarts water to a boil. Add shrimp; simmer for 3 to 4 minutes (longer if shrimp was still frozen), until pink. Do not overcook.
Drain shrimp in colander and rinse with cold water to cool. Peel. If you want more pieces, cut each shrimp in half lengthwise.
Place vinegar-pepper liquid, ginger, garlic, sugar and salt into a blender. Blend until smooth. Put in small saucepan and bring to a simmer.
Place shrimp, onions and scallions in a glass bowl. Add hot sauce and stir to combine well. Cover; chill overnight. Serve with toothpicks.