In a small mixing bowl, combine cream cheese, onion, garlic salt, mayonnaise, and red pepper. Stir until smooth and combined well.
Stir in finely chopped cucumber.
Cover and place in the refrigerator to keep chilled until ready to serve with crackers, toasts, veggies, pretzels, etc.
Optional: Garnish with fresh herbs and cucumber slices.
Notes
If you want a more pureed cucumber cream cheese dip (to use as a spread, for instance) then blend all ingredients in a food processor until smooth. You can also use an electric mixer instead of stirring by hand.