Prepare shrimp and sea shell pasta(if not pre-cooked) Boil pasta until just al dente- drain and cool. Chop each shrimp into 2-3 pieces for the salad.Add lemon juice to shrimp in large plastic container with a lid. add cooked pasta to shrimp.
Pre cut the red onion- I process in chopped until finely minced. Cut the cucumber into bite-size pieces and also cut the grape tomatoes into halves or thirds. Add to shrimp.
Mix the salad dressing and mayonnaise and the dry Hidden Valley Ranch dressing together and then pour on to the salad mixture and mix together and chill in refrigerator for 2 hours or overnight.(stir all again before serving for even distribution of ranch dressing.)