Add the bread crumbs in a bowl filled with milk and let absorb the milk for 30 minutes. Squeeze to remove almost all the milk and keep aside in a big bowl.
In a separate large bowl grate the white onions and add on top the chili flakes along with the cumin, oregano, 1 teaspoon of the smoked paprika and season with the salt and pepper Then add the bread crumbs followed by the minced meat and the olive oil. Mix thoroughly for almost 15 minutes until the mixture becomes light and turns into a whitish mixture. If you want to refrigerate overnight, then lightly brush the mixture with olive oil and cover with plastic wrap.
Next day place a grill pan on medium/high fire.
In the meantime, take the mixture from the refrigerator and while cold form the soutzoukakia in your palms into large bullet patties of about 6-7 cm length.
Go back to your grill pan, lightly brush the soutzoukakia with olive oil and grill for 3-4 minutes each side until nicely charred.
To serve take a big plate and arrange in the centre some Yoghurt Flatbreads and add on top the soutzoukakia whereas the onions and tomatoes to be around them. Sprinkle the parsley and add to the side and on top of the soutzoukakia the Yiaourtlou sauce. Sprinkle on the side the chili flakes and on the Yiaourtlou sauce the remaining paprika.