While the pasta water comes to a boil, whisk together the Greek yogurt, mayonnaise, freshly minced garlic, lime zest, lime juice, cumin, paprika, salt, and cayenne pepper in a large mixing bowl until smooth and well combined. The dressing should be creamy with visible flecks of garlic and bright lime zest throughout. Taste and adjust seasoning as needed—I like to add the full amount of salt here since it helps everything come together better. Set the dressing bowl aside; you'll use this same bowl to toss everything together later.

Bring a large pot of salted water to a rolling boil and cook the rotini pasta to al dente according to package directions (usually 8-10 minutes). While the pasta cooks, rinse and thoroughly drain the black beans, measure out the corn, roughly chop the spinach into 1/2-inch ribbons, and mince the cilantro. Once the pasta is cooked, drain it in a colander and rinse thoroughly with cold water to stop the cooking process and remove excess starch—this ensures the salad stays light and doesn't become gummy.

Add the cooled pasta, black beans, corn, spinach, and cilantro to the dressing bowl and toss gently but thoroughly until all components are evenly coated. The dressing should be creamy and coat every piece of pasta and vegetable. I find that gently folding everything together rather than vigorously stirring helps keep the spinach from breaking down and maintains the texture of the corn.

Taste the salad and adjust seasoning as needed with additional salt, cayenne pepper, or fresh lime juice depending on your preference. The salad can be served immediately while the pasta is still slightly warm, or chilled for 30 minutes to an hour for a cooler version. If you prefer it chilled, add a splash more lime juice just before serving since the flavors mellow slightly after sitting.