Greek Yogurt Salad

I found this recipe from "Smart Cooking  The Costco Way" which is a cook book Costco give away.
I love olive and cheese so I love this recipe.

Ingredients
1/2 iceberg lettuce head chopped
1 romaine heart chopped
2/3 pitted kalamati olives
1 medium cucumber
1/2 medium red onion thinly slices
2 small tomatoes
3/4 cup crumbled feta cheese

Dressing
2 tablespoon plain Greek-style yogurt
1/2 teaspoon dijon mustard
1/2 teaspoon fresh lemon juice
1/4 teaspoon fresh crushed garlic
1/4 teaspoon dried oregano rubbed between palms of hand
3 tablespoon white wine vinegar
pinch of salt and black pepper
1/2 cup extra -virgin olive oil

Preparation Method  
In a large bowl combine lettuces, olives, cucumber, onion and tomatoes. Sprinkle with feta.
To prepare the dressing, combine yogurt, mustard, lemon juice, garlic, oregano, vinegar, and salt and pepper in a small mixing bowl. Slowly whisk in oil until fully blendid.
Pour the dressing over the salad and tossed gently until well coated.