Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Once the water is boiling, stir in the fusilli and return to the boil. Cook uncovered, stirring occasionally, until the pasta has cooked through, but is still firm to the bite, about 8 minutes. Drain and cool by running cold water over the pasta in a colander set in the sink.
Combine fusilli with the cucumbers, onion, tomatoes and olives in a large bowl. Pour the Italian dressing over the salad and stir to combine. Cover and refrigerate for at least 2 hours before serving.