Bring a large pot of water to a boil. Add a generous amount of salt and add fettuccine noodles. Cook according to package directions or until al dente. Remove noodles from water to a strainer, reserving water in pot. Rinse noodles and set aside to cool.
Trim ends of green beans and add to hot noodle water. Remove after one minute then rinse in cold water and set aside.
Peel cucumber and red onion and thinly slice. Seed and core red bell pepper and thinly slice.
To assemble, group fettuccine, green beans, cucumber, red bell pepper, red onion and capers in sections on a serving plate. Mix dressing with champagne vinegar and dress fettuccine noodles then season with kosher salt and pepper. Serve at room temperature.