Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine the Greek yogurt with the cumin, cardamom, turmeric, cinnamon, and salt. Stir until well blended.
Add the chicken strips to the marinade, tossing them until fully coated. Set the mixture aside to allow the chicken to absorb the flavors.
Lightly oil a large rimmed baking sheet with 1 tablespoon of olive oil. Spread the marinated chicken, sliced onions, bell peppers, and peppadew peppers evenly on the baking sheet. Drizzle the remaining olive oil over the top.
Place the sheet pan on the center rack of the oven and bake for 20 minutes, or until the chicken is thoroughly cooked, and the vegetables have become tender. For a more caramelized finish, broil the ingredients for an additional 3 minutes, or until the desired level of char is achieved.
In a separate bowl, prepare the tahini sauce by combining the tahini, garlic, olive oil, lemon juice, water, and salt. Whisk until smooth. The mixture may appear to separate initially, but continue mixing until the sauce becomes thick and creamy.
To serve, warm pita bread and fill it with the roasted chicken and vegetables. Top with the tahini sauce, and garnish with fresh cucumber and tomatoes. Enjoy!