In a large skillet, heat the oil over medium-high heat. Add the garlic, white part of green onion and lemon juice, stirring to combine.
Add chicken pieces and cook for 3 minutes on each side or until the meat is white and the juice runs clear.
Meanwhile, stir-fry zucchini in a skillet coated with olive oil over medium high heat until slightly limp and toss with butter.
Stir the arugula and green onion into the chicken. Toss the chicken mixture with the zucchini noodles, and season with salt and pepper. Serve hot on a large platter.