Cook chicken in a medium/large pot with a lid: place fresh or frozen chicken breasts in pot, cover with approx. 1/3 cup water (for moisture), quarter the lemon and squeeze juice over the chicken, leaving the lemon pieces in the pot to stew. Sprinkle chicken with seasoning salt, italian seasoning, and cayanne pepper, then cover and cook until done, turning once. When the chicken is done, remove lid to allow most of the extra liquid to steam off. When the liquid has mostly evaporated, remove from heat. Slice the meat into large bite-size pieces, and replace the lid.
While the chicken is cooking, slice the peppers, onion, and tomato and sautee lightly in about 2 Tbs olive oil. Sprinkle with garlic and salt to taste. When vegetables are cooked but still firm, remove from heat and keep covered with a lid.
For the cucumber-yogurt dressing, combine the yogurt, cheese, and cucumber in a bowl, adding seasoning salt to taste.
Wrap the tortilla wraps in a lightly damp cloth and microwave until warm (approx 30 seconds).
Serve immediately, fajita-style. (You'll want extra napkins...) Delectable!
P.S. This would be great with grilled chicken, too. Just marinate the chicken in the seasonings and lemon juice before you grill it.