Clean the cucumber, then cut it in small cubes.
Season spelt with oil.
Ricotta cheese mousse: season ricotta with salt, pepper, minced parsley and lemon zest.
Place some spelt over the bottom of glass jars.
Place tuna with ‘nduja on top, then cucumber cubes.
Put the mousse within a sac à poche, and squeeze it within each glass jar. Place a piece of tuna on it and use parsley to garnish, then serve.