Firmly press the cooked jasmine rice into a flat, compact patty or two small cakes.
Heat half of the avocado oil in a non-stick skillet over medium-high heat and fry the rice patty until the bottom is golden and crispy, then flip and repeat.
Pat the tuna steak completely dry with paper towels and season both sides with sea salt and black pepper.
In a separate skillet or the same pan after removing the rice, heat the remaining avocado oil over high heat.
Sear the tuna steak for about 1-2 minutes per side for a rare to medium-rare center, then remove from heat to rest.
In a small bowl, whisk together the tamari, lime juice, toasted sesame oil, and grated fresh ginger to create the zesty dressing.
Toss the sliced cucumber and scallions with one tablespoon of the dressing to make a quick slaw.
Slice the seared tuna against the grain and arrange it over the crispy rice cakes, drizzling with the remaining dressing and serving the slaw on the side.