If using sweet potatoes preheat the oven to 200 degrees Celcius.
When the oven is hot place the sweet potato slices on a parchment covered baking sheet and baked for 10 minutes.
Meanwhile combine about 1 1/2-2 tablespoons of Creme Fraiche with the hot smoked salmon in a bowl. Add lemon juice according to taste.
Next combine about 1 1/2-2 tablespoons of creme Fraiche with dijon mustard and mayonnaise (if using) and 1 teaspoon roughly chopped capers and combine in a bowl. Season with sea salt and lemon juice according to taste.
Peel and rinse the shrimps.
When the sweet potatoes are ready or if using cucumber slices place them on a plate.
Top two slices with the hot smoked salmon salad and top with sesame seeds.
Top two slices with smoked salmon, the capers dressing and top with more capers on top.
Top the last two with about 1 teaspoon each of Creme Fraiche, a shrimp and fish roe. Garnish with dill.