Grate the unpeeled cucumbers on a box grater. Wrap in a kitchen towel and wring out any excess liquid.
Combine the cream cheese, sour cream, lemon juice and hot sauce in a food processor and process until smooth. Season with salt and pepper. Add the cucumbers, chives, parsley, dill and scallions and pulse, stopping to scrape down the sides several times, until pale green and almost smooth. Refrigerate until chilled, at least 1 hour.
Spread the Benedictine on the zucchini and squash slices and garnish with reserved dill fronds.