For the potatoes:
together the chili powder
, cumin, sugar, salt and pepper, to taste, in a small bowl.
Heat the grill
over medium-high heat.
Brush the potato slices with oil on both sides and season with the spice rub on one side. Skewer
2 slices of the potatoes onto 2 skewers (so the potatoes lay flat) and place on the grill, rub side down and cook until golden brown and a crust
has formed, 2 to 3 minutes. Turn the skewers over and continue grilling until the second side is golden brown and the potatoes are just cooked through, 2 to 3 minutes longer. Remove to a platter and immediately drizzle
with green onion vinaigrette, green onions
and chopped cilantro