Bring a 6-quart pot of water to a boil; cook shrimp until bright pink and cooked through, 2 to 2 1/2 minutes. Transfer shrimp using a slotted spoon to a bowl of ice water to cool; drain and pat shrimp dry. Place shrimp in a large resealable bag.
Mix olive oil, salad dressing, garlic, and jalapeno pepper together in a glass or plastic bowl; pour marinade into bag of shrimp, coat shrimp with the marinade, squeeze out excess air, and seal the bag. Marinate in the refrigerator for 20 minutes to 1 hour.
Line a baking sheet with aluminum foil and spread a thin layer of salt over foil.
Preheat the oven's broiler.
Remove shrimp, 1 at a time, from marinade and place on the salted baking sheet. Discard unused marinade.
Place baking sheet on rack furthest away from the broiler. Broil in the preheated oven until shrimp begin to brown and peel back, 7 to 10 minutes. Turn off broiler and crack oven door open for 3 minutes before removing shrimp from oven.