Start by cooking your choice of rice and mixing in lime juice and chopped cilantro for a fresh, citrusy base. This bright rice ties the whole dish together and is incredibly fragrant. Set it aside while you prepare the toppings and tuna.
Place the tuna steaks in a plastic bag or shallow dish. Combine soy sauce, lime juice, and dijon mustard in a bowl or jar, whisking until the marinade is blended. Pour it over the tuna and let it rest in the fridge for at least 30 minutes. This step ensures the fish absorbs all those delicious flavors!
Heat a cast iron skillet over medium-high heat and add sesame oil. Remove the tuna from the marinade, coating it lightly in sesame seeds. When the oil begins to shimmer, sear the tuna on each side for about 30 seconds to 2 minutes. The middle should stay pink for the best texture. Allow it to rest for a few minutes, then slice thinly.
Combine diced pineapple, jalapeño, red onion, cilantro, lime juice, and chile lime seasoning in a bowl. Stir well and taste to adjust seasoning. The combination of sweet, spicy, and acidic flavors gives the dish a tropical flair that pairs beautifully with the savory tuna.
Mix Greek yogurt, lite mayo, sriracha, rice vinegar, and seasonings in a small bowl until smooth. If you prefer an extra kick, add a bit more sriracha. This creamy dressing adds the final touch to the bowl. Set it aside until ready to assemble.
Now for the fun part! Layer the cilantro lime rice at the bottom, then top it with diced bell peppers, cucumbers, pineapple salsa, and avocado slices. Add your seared tuna slices and drizzle the spicy sauce on top. Garnish with green onion for a fresh, vibrant finish.