Process the cottage cheese and milk in a food processor until smooth. Add the scallions, salmon, cream cheese, lemon juice and a pinch of white pepper and process until smooth and creamy. Refrigerate at least 1 hour or overnight.
Cut the cucumbers into 3/4-inch-thick rounds, discarding the ends. Using a small spoon, scoop the seeds and some of the flesh out of each round to form a small cup.
Fill each cup with about 2 teaspoons of the salmon whip and sprinkle with the chives. Cover and refrigerate until ready to serve, up to 1 hour.