1. The night before cooking, salt each fillet with a thin layer of kosher salt, then let sit in the fridge overnight. In the morning, pat dry.
2. Prepare a frying pan with oil and set on high heat.
3. For the salmon, sprinkle over the spices and pat them onto the fish. When the oil is hot, sear with the skin side up for four minutes, then flip and cook another three minutes. Remove to a plate lined with paper towels.
4. For the tuna steak, rub all over with egg white. This will help create a really crispy crust. Pat on sesame seeds to cover completely. Set in the freezer for one hour before cooking (this step is optional but highly recommended!). Sear in hot oil for two minutes per side. Remove to a plate lined with paper towels.
5. For the turbot, sprinkle over the spices and pat them onto the fish. Sear a couple minutes per side. I use two spatulas because it’s very delicate. The crust is a little sticky, so place directly onto a plate sans paper towels.