In a mixing bowl, combine honey, soy sauce, minced garlic, rice vinegar, and red pepper flakes (if using). Stir well to create the marinade.
Add the salmon pieces to the marinade, making sure each piece is thoroughly coated. Set aside to marinate for about 5 minutes while preparing the cornstarch coating.
In a separate bowl, season the cornstarch with salt and pepper.
Remove the salmon pieces from the marinade, letting any excess drip off, then coat each piece evenly with the seasoned cornstarch, shaking off any extra.
Heat the vegetable oil in a frying pan over medium heat. Once hot, carefully place the coated salmon bites in a single layer, avoiding overcrowding.
Cook the salmon bites for approximately 3-4 minutes on each side, until they turn golden brown and crispy.
Remove the cooked salmon bites from the pan and transfer them to a plate lined with paper towels to drain any excess oil.
Pour the remaining marinade over the crispy salmon bites and garnish with chopped green onions before serving.