Heat a small skillet on medium high. Add almonds and cook, stirring, until they turn golden. Transfer to a bowl and set aside. Grill the chicken on a hot grill until just cooked through, about 3 to 5 minutes on each side. Remove to a warmed plate and cover. While the chicken is cooking, heat the oil in a saucepan. Add the onion, chile, and jerk seasoning and cook, stirring, until the onion is translucent but not brown, about 5 minutes. Add 1 cup of orange juice and boil 5 minutes. Combine the arrowroot and remaining orange juice and stir into the sauce to thicken. Add the salt and orange zest. Divide the spinach among 4 dinner plates. Place the chicken pieces on top and cover with the sauce. Sprinkle with the toasted almonds, orange segments, and cilantro, dividing these evenly among each plate. Makes 4 servings.