Greek Salad Sandwich

1 medium cucumber, seeded and chopped
1/2 cup plain Greek yogurt
2 roasted red peppers, chopped
2 garlic cloves, minced
2 tablespoons fresh dill, chopped or 1 teaspoon dry
3 tablespoons apple cider vinegar, divided
2 tablespoons extra virgin olive oil
1/2 teaspoon dry oregano
1 small cucumber, thinly sliced
12 pitted Kalamata olives, chopped
6 peperoncini, stemmed and cut into thin rings
4 radishes, cut into matchsticks
2 plum tomatoes, coarsely chopped
1 cup kale, thinly sliced
1/2 small red onion, thinly sliced
1 cup feta, crumbled
3 pita breads, cut in half

1. Put the chopped cucumber in a kitchen towel and squeeze out as much liquid as possible.  Combine the yogurt, peppers, garlic, dill and 2 tablespoons vinegar with the cucumber and stir well. Season to taste with salt and pepper. 
2. In a large bowl, combine 1 tablespoon vinegar with the olive oil and oregano. Add all the remaining ingredients and toss well.  Season to taste with salt and pepper. Spread 3 tablespoons of the yogurt mixture in each pita half.  Fill with the salad and serve immediately.