Peel and grate cucumber. Squeeze as much liquid out as possible - either in a cheesecloth, clean kitchen towel or a fine mesh strainer. Otherwise you will have a very liquidy spread!
In a food processor, combine strained cucumber, vegan cream cheese, vegan mayo, chopped onion, salt and pepper. Mix until well blended.
Lightly toast bread (optional). Cut crusts off the bread and slice in whatever shape you like. Spread a generous amount of Benedictine spread on. Top with another slice of bread and serve.
Notes
If you are using gluten free bread, I would definitely consider toasting the bread.As you can see in the photographs, I did not, and I regret it. Brown rice bread tastes way better toasted!*Update: A reader recommended in the comments below Northern Bakehouse millet chia bread. Talk about game changer! It is soft and fluffy like white bread and I highly recommend it!