Shrimp Scampi Zoodles

Name: Shrimp Scampi Zoodles
Ingredients: 4 medium zucchini, washed and trimmed; kosher salt; 1 lb. medium shrimp, peeled and deveined; Freshly ground black pepper; extra-virgin olive oil; 3 cloves garlic, minced; 1 small onion, choped; 1/2 tsp. crushed red pepper flakes; 1 1/2 c. dry white wine; Zest and juice of 1 lemon; 3 tbsp. cold unsalted butter, cut into 3 pieces; 1/4 c. chopped parsley; 1 lemon, thinly sliced