Combine the two types of sesame seeds in a shallow dish.
Season the tuna with salt and pepper.
Dredge the tuna in the sesame seed mixture.
Heat the olive oil in a skillet to high heat then add the tuna.
Cook for 1 to 2 minutes until seared then turn and sear on the other side.
Remove the tuna from the skillet and let the tuna rest while you reheat the skillet with the coconut oil.
Fry the green beans in the oil for 5 minutes then serve with sliced tuna.