I recommend 21/25 ct. shrimp. Boil, peel, and if you’re the persnickety type, devein.
For five pounds of shrimp, mix well a cup of rice vinegar, a cup of vegetable oil, a small jar of capers (with liquid), two tablespoons of good Italian herb blend, and a tablespoon of coarse black pepper. Add with two small white onions, very thinly sliced, two fresh bay leaves, and a cup of diced sweet peppers.
Toss until shrimp are coated, cover and chill overnight, stirring occasionally. In season, add diced ripe summer tomatoes before spooning over leaf greens and drizzling with marinade.