Bring A Large Pot Of Lightly Salted Water To A Boil. Add The Egg Noodles, And Cook Until Tender, About 6 Minutes. Drain. While The Noodles Are Cooking, Mix Together The Sour Cream, Milk, Garlic And Salt; Taste And Adjust Seasoning If Desired. Stir Into Drained Noodles Along With Peas And Tuna. Heat Through Over Low Heat, And Serve.