01 - Whisk together soy sauce, honey, sesame oil, ginger, garlic, rice vinegar, and Sriracha in a small bowl until well combined.
02 - Place cod fillets in a shallow dish. Reserve 2 tablespoons of marinade for glazing. Pour remaining marinade over fish and let sit for 10-15 minutes.
03 - Set oven broiler to high heat. Line a baking sheet with foil and lightly oil the surface.
04 - Combine reserved marinade with water and cornstarch in a small saucepan. Whisk until smooth, then heat over medium-low heat for 1-2 minutes until thickened.
05 - Remove cod from marinade and place on prepared baking sheet. Brush thickened glaze evenly over each fillet.
06 - Broil for 8-12 minutes until fish is opaque and flakes easily. Brush with additional glaze halfway through cooking.
07 - Transfer cod to serving plates. Sprinkle with toasted sesame seeds and sliced green onions. Accompany with lime wedges if desired.