Prepare the Sesame Teriyaki Salmon according to the package instructions. Set aside and flake the salmon into small chunks with a fork.
Heat 1/2 tablespoon butter in a medium nonstick skillet or wok over medium-high heat. Add yellow onion and cook, until translucent, about 3-4 minutes.
Add minced garlic and saute until fragrant, about 2 minutes.
Add the leftover rice in an even layer. Cook, without stirring, 2 to 3 minutes, or until the bottom becomes slightly crispy. Add the cauliflower rice (if using), frozen peas and carrots, continue to cook, stirring occasionally, 2 to 3 minutes, or until combined.
With a spoon or spatula, push the rice to one side of the skillet. Crack the eggs onto the other side of the skillet or wok. Cook, constantly stirring the egg, until cooked through. Mix the rice, cauliflower and egg to thoroughly combine. Stir in the soy sauce and sesame oil.
Gently fold in the flaked Sesame Teriyaki Salmon and toss, serve immediately garnished with scallion greens and sesame seeds.