I don't have a grill or grill pan; how can I cook these?

If you don't have a grill or grill pan, skip threading the chicken onto the skewers and cook the chicken pieces in a lightly greased nonstick or cast iron skillet over medium heat. If you don't want to cook them on the stovetop, you could try using the air fryer or oven, but I haven't done this myself.

Can I make these skewers smaller for an appetizer?

Yes! If you want to serve these as an appetizer, cut the chicken into smaller pieces or thin strips and thread them onto 6-inch skewers . Keep in mind that smaller pieces of chicken will cook faster, so keep a close eye on your grill.