In the bowl of a food processor, combine the zest and juice of 1 lemon, leaves from 5 sprigs oregano, 2 cloves garlic, red pepper, salt, and black pepper; pulse to combine. With motor running, slowly pour in pecan oil, and pulse until combined. Set aside.
Score snapper on both sides with parallel slices cutting down to the bone, about two inches apart between the fins and the tail. Fill the fish’s cavity with lemon slices, remaining 5 oregano sprigs, and remaining 3 cloves garlic.
Rub reserved herb mixture onto the snapper on both sides being careful of the dorsal fin, which can be very sharp. Cover, and refrigerate 1 to 2 hours.
Rub grill rack with pecan oil. Prepare grill for direct and indirect grilling, and heat to medium- high (350° to 400°). Place snapper over direct heat until it begins to char, 2 to 3 minutes per side. Carefully move snapper to indirect heat, and cover grill. Cook 4 to 7 minutes more, depending on the size of the fish and temperature of the grill. Carefully transfer snapper to a serving platter, and serve immediately.