Preheat oven to 400 degrees Fahrenheit. Line some baking sheets with aluminum foil or parchment paper, set aside.
Mix cream cheese and feta together in a bowl, set aside.
Heat olive oil in a saute pan. Finely chop onion and garlic, add to pan. Thinly slice spinach leaves, discarding stems, and add to pan. Cook until spinach begins to wilt & onions are translucent. Season with a bit of salt & freshly ground black pepper. Pour spinach and onions into bowl, & mix well with a spoon.
Lay out the wonton wrappers on a large cutting board, or any clean workspace, and brush edges with olive oil. Put a teaspoon of the cheese-spinach mixture in the middle of each wrapper, and fold once until opposite corners are touching; forming a triangle. Brush liberally with olive oil and arrange on baking sheets so that they are not touching. Bake for 15 minutes, or until golden brown.
[section]For the tzaziki[/section]
Pour yogurt into a large bowl.
Finely chop cucumber & garlic, mix into yogurt.
Add lemon juice, and season with salt & white pepper, to taste. Enjoy!