Spread the Rösti on a baking tray. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-20 minutes. Wash the herbs, shake dry and chop. Season quark with salt and pepper, stir in herbs, up to 1/3 of the dill.
Wash and clean the cucumber and slice it into thin slices. Peel and finely chop the onion. Mix vinegar, salt, pepper and sugar. Fold in the oil. Stir in onion. Mix vinaigrette, remaining dill and cucumber.
Remove the Rösti from the oven. Arrange the hash browns, salmon slices and some curd on plates. Garnish with lemon wedges and dill.