Cook the macaroni in a large pot of salted boiling water for about 10-12 minutes until tender. Drain and rinse with cold water.

Finely dice the red onion and chop the red and green peppers. Set aside in a large mixing bowl.

Add the cooled macaroni to the vegetables. Gently fold in the drained canned tuna and grated hardboiled eggs.

Combine mayonnaise and apple cider vinegar in a separate bowl. Whisk until smooth, then adjust seasoning with salt and pepper.

Pour the dressing over the macaroni mixture and fold gently until well combined.

Cover and chill the salad in the refrigerator for at least 1 hour before serving.