Too late to help you, but a very easy version is a part of the traditional Louisville, KY Derby Day lunch: Benedictine sandwiches (nobody I know has any idea why they're named after monks, or why they're dyed electric-green, but so it goes)
Benedictine Sandwiches
1 large cucumber
8 ounces cream cheese
2 tablespoons grated onion
1 tablespoon mayonnaise
1/8 teaspoon salt
Dash green food coloring
Peel, seed and grate cucumber. Spread grated cucumber between layers of paper towels or coffee filters, roll, and twist out the liquid. Blend togetheror food processer cucumber, cream cheese, onion, mayo and salt. Add food coloring, one drop at a time, until mixture is light, bright green. Spread mixture between two pieces of white, crustless bread and cut into triangle sandwiches. The Benedictine can also be served as a dip.
I agree about the pressing; you can do it by rolling your sandwich bread ahead of time with a rolling pin.