In a large pot over medium heat, bring water to a boil. Once boiling add the kosher salt. Place linguini in the pot and cook according to package directions or until al dente.
Meanwhile, in a skillet over medium low heat, melt the butter. Add the olive oil, garlic, and salt. Cook for 1 minute. Add the shrimp. Cook until the shrimp turns pink and is no longer translucent, about 6 minutes. (3-4 minutes per side).
Remove from heat. Add the parsley, lemon juice, red pepper flakes, and black pepper. Stir to combine.
When pasta is finished cooking, drain. Add the pasta noodles to the shrimp and lemon mixture. Toss to coat. Garnish with additional parsley and salt and pepper to taste. Serve immediately.