Rub the tuna with 2 teaspoons neutral oil and season with 1 teaspoon kosher salt and 1/2 teaspoon coarsely ground black pepper if using. Place the tuna steaks on the grill. Cover and cook until the tuna releases easily from the grill, about 1 1/2 minutes.
Get your skillet real hot. Rub cracked pepper on both sides of the tuna steaks. Pour a little oil into the hot skillet. Seared each side for about 5 minutes on both sides without disturbing them. You can see the meat cooking it’s way up the steak. I like it rare as you can see but you can cook it longer if your prefer.
Heat grill on high flame. Cut the squash lengthwise into ¼-inch thick slices. Slice the avocados in half and remove the pits. Brush the squash, avocado, and onion slices with the reserved tablespoon marinade. Remove the tuna steaks to a plate, discarding marinade. Coat each side of each tuna steak with 1 teaspoon sesame seeds.
This pepper tuna steak recipe is simple but elegant. These meaty and tender tuna steaks taste even better with the simple lemon dijon cream sauce for only 2.9g net carbs. Best of all you can make this easy low carb fish dinner in just 15 minutes!