Clean, wash and drain the peppers, cucumber and tomatoes. Cut cucumber into slices, tomatoes into wedges and peppers into large cubes. Peel onions and cut 2 into fine slices.
Finely dice the remaining onion. Peel the garlic and press it through a garlic press. Wash parsley, dab dry and chop. Mix vinegar, salt, pepper and oregano. Add the oil and set the vinaigrette aside.
Place the minced meat, egg, breadcrumbs, garlic, diced onion and parsley in a mixing bowl. Season with salt, pepper and cinnamon and knead everything well. Cut feta cheese into 10 pieces. Form 10 longish dumplings from the minced dough and press 1 sheep's cheese piece in the middle of each.
Heat the oil in a large frying pan. Put 2 bifteki lengthwise on a skewer and place them in the hot oil. Fry for approx. 8 minutes, turning. Mix the salad with the vinaigrette and arrange on a plate with olives.
Place hot bifteki skewers on the plate and serve garnished with fresh oregano leaves as desired. Serve with fresh flat bread and Tsaziki.