Steps
- First, heat a non-stick skillet or frying pan over medium-high heat. Add sesame oil and let it heat up until shimmering, but not smoking.
- While the pan heats up, season the tuna with soy sauce, rice vinegar, and mirin (if using). Coat the tuna evenly with the seasoning mixture.
- Once the pan is hot, place the tuna in the pan for about 30-45 seconds on each side to sear the outside, leaving the inside raw. Remove from heat.
- Allow the tuna to rest for a minute before slicing it into thin pieces, about 1/4 inch thick, using a sharp knife.
- Arrange the sliced tuna on a plate. Garnish with toasted sesame seeds, cucumber slices, and spring onions. Serve with lime wedges and optional wasabi paste.