In a small jar, add olive oil, vinegar, zest, lemon juice, seasoning, oregano and pepper. Add lid and shake until dressing is combined. Taste; season with salt and pepper.
On two plates, add orange slices to each, top with half of the tomatoes, cucumbers, olives and onions on to each plate. Shake dressing and drizzle over salads. There may be dressing left over. It can be stored in the refrigerator for 2 weeks. Garnish with Italian parsley if desired.