As Alton Brown says, “I never send breast to do what thighs could do better (and cheaper).” Grilled chicken gyros are no exception. You get a juicier piece of meat that works much better as a leftover (chicken breasts tend to get dry and I find they don’t taste as good on day 2) with the added benefit of being kissed by fire, imparting that flavor into the dish. I also find that cooking with the skin on and the bone in helps with keeping the chicken moist.
PRO TIP: don’t bother trying to cut the bone out. Let the chicken cool, and then bone it caveman style. Just slide your finger along the bone and pull the meat off. It’s much easier to do than attempting to cut it out, and it saves your blade from dulling on the bone. You also look much cooler doing it that way.
PRO TIP #2: If you really want to kick this up a notch, fire roast the tomato as well. Cook it whole over direct heat turning a few times to just get a char on all sides. If you char it too much, the skin will just slide off (which may be fine for some recipes, but we want to bring that flavor into the gyro sauce). Make sure to let it cool, as the liquid inside will be boiling hot when you cut into it if you do so right away.