Grate the cucumber on the large holes of a box grater. Wrap the grated cucumber in dampened cheesecloth and squeeze to remove as much liquid as possible.
Combine the cream cheese, yogurt and mayonnaise in a stand mixer fitted with the paddle attachment. Mix until smooth, about 1 minute. Add the cucumber, red onion and dill, and mix until combined, another 30 seconds. Season with salt and pepper. Scrape into a serving bowl, cover and refrigerate for 1 hour.