1. In a large sauté pan, melt the butter over medium-high heat.
2. Add the rinsed and drained capers and set aside off the heat.
3. Coat each side of the tuna steaks with olive oil, kosher salt and pepper.
4. Place the tuna steaks on preheated grill at medium-high heat.
5. Grill for one and a half to two minutes on each side.
6. Heat the sauce on medium and squeeze the lemon into the sauce..
7. Plate the tuna steaks and spoon the sauce over the tuna steaks and serve.