For chicken, combine all ingredients and form into 2" balls and skewer (about 3-4/skewer). Generously spray chicken with cooking oil and place on a hot oiled grilled using a spatula to transfer them (to keep the delicate skewers from falling off). Gently flatten balls a bit, this will help them cook faster. Grill until fully cooked, turning until browned on all sides.
For the croutons, in a bowl toss the bread cubes with a bit of oil until lightly coated and sprinkle with some of the seasonings. Toast in a skillet until lightly golden on all sides.
For the dressing, place the egg yolk, lemon juice and mustard into a blender, pulse to combine. With machine running slowly drizzle in the oil in a very thin stream through the top of the lid. Once all the oil has been added and emulsified, pour into a dish and whisk in remaining ingredients.
To serve, fill each lettuce leaf with a some grilled chicken balls that have been pulled off the skewers, croutons, a drizzle of dressing, a squeeze of lemon and a sprinkle of cheese.
Notes
You can also wrap the whole thing in a GF tortilla wrap!