Ahi Tuna with Tahini Lime Sauce

Ahi Tuna with Tahini Lime Sauce

Tuna is a wonderful fish to marinate. It absorbs aromatics from the marinade and adds infinite oomph to the tuna. This simple marinade is a medley of Asian seasonings that are a balance of umami, sour, salty, and spice. Before running off to the supermarket, read the notes to learn more about Ahi tuna.

*The tahini sauce is completely optional (but delicious!).

Prep time: 15 min (+ 2 hr to marinade) | Cook time: 3 min | Yield: 4 servings 


For the marinade and tuna:

  • 2/3 cup avocado oil
  • 2 tablespoons toasted sesame oil
  • 3-4 tablespoons coconut aminos
  • 2 tablespoons fresh lime juice, about 1 lime
  • 1 tablespoon fresh ginger, grated
  • 3-4 cloves garlic, minced
  • 2 dashes hot sauce 
  • 2 or more tablespoons avocado oil, for cooking
  • 4 tuna steaks, 4-6 ounces each (see notes)

For the Tahini Lime Sauce:

  • 1/3 cup tahini, well stirred if possible
  • ¼ cup freshly squeezed lime juice, about 2 limes
  • 1 tablespoon coconut aminos
  • 2 teaspoons honey
  • 2-3 dashes hot sauce or ¼ teaspoon crushed red pepper flakes
  • Pinch Celtic or pink Himalayan salt
  • 3 to 6 tablespoons water


To marinate the tuna:

Whisk together all ingredients in a non-reactive bowl except for the oil for cooking and tuna. Add the tuna to the marinade, cover, and refrigerate for 2 hours. You can also marinate the tuna in a sealed plastic bag.


To sear (if using sushi-grade):

Place a large sauté pan over high to medium-high heat and let the pan get hot. If you have a cast iron pan, it will give you the best results.

When hot, add 1 tablespoon avocado oil and wait until it shimmers. Place tuna in the hot oil and sear for 30 seconds to 1½ minutes to form a slight crust; flip and sear the other side. The inside should remain pink.

Tip: You may want to cook in two batches to avoid crowding. If so, you may need to use the additional tablespoon of oil. Again, be sure the oil is very hot.


If the tuna is not sushi-grade:

Fully cook to an internal temperature of 145 degrees F.

Reduce cooking heat to medium and skip the sesame crust, because it will burn. Brush with avocado oil to keep moist. Depending on thickness, it could take 4-5 minutes per side. 


To make the tahini lime sauce:

In a bowl or blender add all ingredients for the Tahini Lime Sauce except for the water. Blend and add 1 tablespoon water at a time until you get the consistency you want (see notes). Keep refrigerated.


Optional sesame seed crust: 

Spread ¼ cup or more black, white, or combined sesame seeds on a flat plate. When you take the tuna out of the marinade hold the fish so the excess marinade drips off, place it on top of the sesame seeds and coat one side, pressing to embed the seeds. Flip to coat the second side. Firmly press the seeds into the fish.



Sushi grade Ahi tuna is yellowtail tuna that has been flash-frozen as soon as it is caught, killing any bacteria and parasites. Saku tuna is another name for sushi grade Ahi. It is cut into a boneless, skinless block, vacuum sealed, and sold frozen. This is often used in restaurants.

Because tahini is made from ground sesame seeds, the sesame oil in it tends to separate, making it difficult to recombine, so you may need to use a blender.

This sauce recipe also makes a delicious salad dressing. For that, you might want to thin it more than you do for a sauce.