Bring a large pot of salted water to a boil. Cook the macaroni according to the package directions until al dente. Drain and run under cold water to stop the cooking.
Prep the vegetables and cube the cheese while the pasta cooks. (see note)
In a small mixing bowl, whisk together the mayo, vinegar, mustard, sugar, salt, dill, garlic powder, onion powder, black pepper, and pepper flakes until smooth.
Transfer the cooked pasta to a large serving bowl. Pour the dressing over top, and stir until evenly coated. Add the veggies and cheese and stir until mixed. Serve immediately.
Notes
To tone down the raw onion taste, soak the diced onion in cold water for 5 minutes. Then drain and pat dry a bit with a paper towel.
If you're worried about spice level, start with 1/4 teaspoon of red pepper flakes. Mix the dressing and add more flakes as desired.
For other great add-in options, try chopped hard-boiled eggs, cucumber, carrots, peas, corn, crumbed bacon, and olives.
Store any leftovers in an airtight container in the fridge for up to 5 days.