Cook the tricolor rotini according to the package directions until al dente.
Drain the pasta thoroughly.
Rinse the pasta under cold water until it is no longer hot.
Alternatively, allow the pasta to cool at room temperature or refrigerate it until fully cooled.
Place the cooled rotini in a large mixing bowl.
Add the tomatoes, cucumber, sliced red onion, black olives, and cubed sharp cheddar cheese.
Pour approximately 3/4 of the Italian dressing over the pasta mixture.
Toss until the pasta, vegetables, olives, and cheese are evenly coated with the dressing.
Cover the bowl tightly.
Refrigerate the pasta salad for at least 30 minutes to 1 hour to allow the flavors to blend.
Before serving, add the remaining Italian dressing.
Toss again until well combined.
Serve chilled.
Store any leftovers in an airtight container in the refrigerator for up to 3 days.