Step 1

To make the relish: In a small bowl, stir the onion, capers, lemon juice, dill, and mustard seeds. Season to taste with salt.

Step 2

To make the tartines: In another small bowl, mix the cream cheese, creme fraiche, and chives to blend. Season to taste with salt.

Step 3

Spread the cheese mixture over the toasted slices of pumpernickel and baguette. Cut each slice of the pumpernickel bread into 3 rectangular pieces. Top each with 1 salmon slice, and then top each with a generous spoonful of the relish. Transfer the tartines to a platter. Finely grate the lemon peel over each and serve.