1. Fill a large bowl with ice and water. Bring a medium pot of water to a boil over high heat. Add 2 teaspoons salt and the shrimp, and cook until bright red and cooked through, 4 to 5 minutes. Transfer shrimp to ice bath, and let cool. Drain and pat dry.

2. Peel shrimp, and place in a large bowl. Add capers, lemon zest, and mayonnaise, and stir to combine. Add remaining 3/4 teaspoon salt, the pepper, and dill. Refrigerate shrimp salad until ready to use.

3. Slice pitas in half and open, being careful not to rip the bottom. Fill with shrimp salad, lettuce, and cucumber slices.