Cook the rotini according to the package directions; drain. Rinse with cold water; drain well.
Combine the rotini and the next 9 ingredients (through parsley) in a large bowl; toss gently.
Combine olive oil, garlic, lemon juice, salt, pepper, and oregano in a jar. Cover tightly and shake vigorously. Pour the dressing over the rotini mixture; toss gently to combine. Cover and chill thoroughly.