Tuna steaks are a favorite around here. But if you don't make them right, you end up with a dry brick. So here's how I do mine.
Using a stainless steel pan heated very hot (you can feel the heat when you hold your hand 6" above the pan), put in 1 tsp oil and roll it around.
Then place the seasoned tuna steak in.
It needs to sizzle and crust - this should take about 3 minutes.
Is it ready? Jostle the pan or try to lift; if it sticks, it's not ready.
Remove from the heat and flip the tuna steak. Do NOT put it back on the heat.
Put a pat of butter and some lemon juice in the pan along with small diced a shallots, stirring until the shallots are translucent.
Serve immediately with drizzle of the juice.
What you're looking for is a slightly pink center for well-done, or a red strip through the middle for rare.