Cook the rice according to package directions. While it’s still warm, stir in the rice vinegar and sea salt until evenly seasoned.
Remove the salmon skin by gently pulling it off, then cut the salmon into bite-size pieces. Toss the pieces with cornstarch until lightly coated.
Heat the sesame oil in a large skillet over medium-high heat. Add the salmon in a single layer and sear for about 3 minutes without moving it, until the bottoms are browned and crisp.
Flip and continue cooking, turning as needed, for 5 to 6 minutes total until the salmon is crisp on multiple sides and flakes easily.
In a small bowl, whisk together the soy sauce, honey, ground ginger, and sesame seeds until the honey dissolves. Pour into the skillet and toss the salmon for 1 to 2 minutes, until the sauce clings and looks glossy.
Assemble bowls with rice, salmon, avocado, cucumbers, shredded carrot, and green onions. Add spicy mayo and nori if using.
For meal prep, divide rice and salmon evenly into 4 meal prep containers, then add cucumbers and carrot (keep avocado, nori, and spicy mayo separate if possible). Let cool completely, about 15 to 20 minutes, before sealing lids. Store in the fridge for up to 4 days.