Preheat oven to 425°F (220°C).
In a bowl, combine chicken with garlic, olive oil, lemon juice, cumin, smoked paprika, salt, curry powder, and black pepper. Marinate for 30 minutes.
In another bowl, mix all tzatziki ingredients until smooth. Chill until ready to serve.
Toss sliced peppers with olive oil and salt and spread on a sheet pan.
Place marinated chicken on a separate sheet pan in a single layer.
Roast both pans for 10–15 minutes, until chicken is cooked through and peppers are lightly charred.
Arrange chicken, peppers, tzatziki, and all toppings on a platter.
Serve with warm pita and let everyone build their own pitas, bowls, or salads.