In the work bowl of a food processor, pulse together salmon, cream cheese, chives, and garlic until smooth. Transfer salmon mousse to a small bowl, and cover with plastic wrap. Refrigerate for at least 1 hour.
Cut 12 (ΒΌ-inch-thick) slices from cucumber. (Reserve remaining cucumber for another use.) Blot cucumber slices between paper towels. Let stand on paper towels until ready to assemble.
Place salmon mousse in a pastry bag fitted with a large star tip (Wilton #1M). Pipe onto cucumber slices. Garnish with chives, if desired. Serve immediately.
Recipe by TeaTime Magazine at https://teatimemagazine.com/salmon-mousse-bites/