Combine yogurt, garam masala, lemon juice, lemon zest, grated ginger, and curry powder in a gallon-sized resealable plastic bag.
Slice each chicken thigh lengthwise into 3 or 4 slices, add to the bag with the marinade, and refrigerate for 30 to 60 minutes.
Preheat the oven to 400 degrees F (200 degrees C) and move an oven rack to the center of the oven. Line a sheet pan with aluminum foil.
Thread chicken thigh pieces onto six 15-inch metal skewers and place crossways across the prepared sheet pan, resting the ends of the skewers on the raised edges of the pan.
Bake skewers in the preheated oven for 15 minutes. Remove from oven.
Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Broil chicken skewers for 3 minutes until meat is lightly charred, watching closely.