For the tuna cream, put the tuna in oil in a bowl. Before doing this, collect half of the oil in a pan. In this pan, fry the chopped onion until lightly translucent, add to the tuna. Add tartar sauce, cream cheese, lemon, garlic, dill and pickles and roughly puree with a hand blender. Chop 2/3 of the cress and add with the lemon juice (including the pulp, without the seeds). Likewise, stir in the grated yellow beets and a little white pepper. Let soak in the refrigerator for one to two hours. Then season again with salt and pepper.
Wash the cucumber and peel lengthways with a canning knife. Cut into 2 cm thick slices. Hollow out these slices from above with a small ball cutter but still leave a base. Fill with the cream and garnish with the rest of the cress. If you like it particularly noble, you can puree a little finer and use a piping nozzle to fill it. Especially in summer, the whole thing comes back in the fridge for an hour. Then serve and garnish as desired.
Annotation:
This tuna cream here is more Nordic than Mediterranean, without tomatoes and southern spices. The only thing you can`t do without is the lemon.
The cream as such also tastes great on crackers, small pumpernickels, toasted bread or baguette slices. But here is a variant in cucumber. Finger food with a difference, fresh and also suitable for people with gluten allergies.