Combine paprika, onion powder, garlic powder, oregano, thyme, salt and red and black peppers in small bowl; rub on all surfaces of chicken. Grill chicken on covered grill over medium-hot coals 10 minutes per side or until chicken is no longer pink in center. Cool slightly. Cut into thin strips.

Wrap 2 pita bread rounds in paper towels. Microwave on HIGH 20 to 30 seconds or just until warm. Repeat with remaining pita breads. Cut in half horizontally.

Divide spinach, chicken strips, tomato slices, cucumber slices and ranch dressing among pita bread halves. Serve warm.