For salad: Fill a large Dutch oven halfway full with water; add salt. Bring to a boil over medium-high heat. Add pasta; cook until almost tender, about 7 minutes. Add shrimp; cook until shrimp are pink and firm, about 2 minutes. Drain.
In a large bowl, combine pasta mixture, bell peppers, banana peppers, green onion, and zest. Cover and refrigerate until chilled.
For dressing: In a small skillet, cook bacon over medium heat until crisp. Remove bacon using a slotted spoon, and let drain on paper towels. Reserve 2 tablespoons drippings.
In a small bowl, whisk together mayonnaise, sour cream, dill, milk, parsley, salt, pepper, and reserved 2 tablespoons drippings. Pour over pasta mixture; toss well. Sprinkle with bacon.