This sauce is also nice on Belgian endive spears or boiled new potatoes.

Set aside 1 teaspoon caviar.
Place crème fraiche in medium bowl.
Top with chopped chives, mustard, and remaining caviar.
Sprinkle with pepper.
Gently stir just until combined (over-stirring will cause crème fraiche to soften).
Top with remaining caviar.
Cover; chill until cold. (Can be made 1 day ahead. Keep chilled.)
Place salmon on platter.
Garnish with lemon and chives.
Serve with sauce and cocktail bread.