Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.
In a large mixing bowl, combine the cooked pasta, cherry tomatoes, corn, bell pepper, red onion, and cilantro.
In a small bowl, whisk together the olive oil, lime juice, garlic powder, cumin, salt, and pepper.
Pour the dressing over the pasta salad and toss gently to combine all ingredients.
If using, gently fold in the diced avocado just before serving.
Chill the pasta salad in the refrigerator for at least 30 minutes to allow the flavors to meld. Serve cold or at room temperature.