Heat oil in a large skillet or wok over medium heat.
Sauté onion for 3-4 minutes, then add frozen veggies and cook for another 1-2 minutes, until softened. Add garlic and cook for another 30 seconds.
Add flaked salmon to the pan and stir to combine.
Push everything to one side of the pan. Pour the beaten eggs into the empty side and scramble until fully cooked.
Mix in rice, soy sauce, sesame oil, (salt, pepper, and red pepper flakes if using) Stir well to coat everything evenly.
Cook for 2-3 more minutes, stirring occasionally until everything is heated through. Top with green onions, extra soy sauce, and sriracha if desired.