In a small bowl, whisk together soy sauce, sesame oil, grated ginger, minced garlic, honey, and rice vinegar to create the sauce mixture.
In another small bowl, mix cornstarch and water until smooth and set aside.
Pat the white fish fillets dry with paper towels and season both sides lightly with salt and freshly ground black pepper.
Heat vegetable oil in a large non-stick skillet over medium-high heat.
Add the fish fillets to the skillet and cook for about 3-4 minutes on each side until the fish is opaque and flakes easily with a fork. Remove the fish from the skillet and set aside on a warm plate.
In the same skillet, add broccoli, carrots, and snap peas. Stir-fry the vegetables for 3-4 minutes until tender-crisp.
Pour the prepared sauce mixture over the vegetables and bring to a gentle simmer.
Stir in the cornstarch slurry and cook for 1-2 minutes until the sauce thickens.
Return the cooked fish fillets to the skillet and spoon the sauce and vegetables over the fish to coat evenly. Cook for an additional 1-2 minutes to heat through.
Transfer the fish and vegetables to serving plates. Garnish with sliced scallions and toasted sesame seeds before serving.