Step #1 Make mayonnaise: mix all mayonnaise ingredients in a small bowl; stir well to mix; cover & put in the fridge until ready to use.
Step #2 Prepare a med-hot fire in a charcoal grill with a cover; or preheat a gas grill to med-high.
Step #3 Make the patties: place the almonds in a small fire-proof skillet on the grill; stir frequently until lightly golden brown, 5-10 mins; set aside to cool.
Step #4 In a bowl, mix the chicken, green onion, egg whites, & apple; season this with salt & pepper; mix well.
Step #5 Divide mixture into 6 equal portions; shape each portion into patties to fit the rolls.
Step #6 Finely chop the toasted almonds & mix with the bread crumbs & curry powder in a shallow bowl/pie plate, stirring well.
Step #7 Coat both sides of the patties with the almond mixture, pressing carefully to adhere.
Step #8 Brush the grill rack with vegetable oil; place the patties on the grill rack, cover, & cook, turning once, just until the juices run clear when the patties are pierced in the center (about 4 mins on each side).
Step #9 During the last few mins of cooking, cut side down, place the rolls, on the outer edges of the rack to toast lightly.
Step #10 Assemble burgers: decoratively fan several spinach leaves on the bottom roll; top each with a patty & a generous dollop of the mayonnaise; add the roll tops & serve.