Preheat oven to 450º.
In a large mixing bowl, whisk the sauce ingredients together.
Add the green beans, tomatoes and onions and toss to coat with the sauce.
With a large slotted spoon or spatula, transfer the vegetables to a large baking sheet [12 x 15 x 1 inch]
Keep the vegetables to one side and make sure they are spread out in one layer.
Add the halibut fillet strips to the remaining sauce, toss to coat.
Transfer the halibut fillet to the baking sheet next to the vegetables and pour any remaining sauce on top.
Lightly sprinkle the halibut and vegetables with a little seasoned salt.
Bake for 15 minutes; then transfer the baking sheet to the top oven rack and broil for another 3 to 5 minutes, watching carefully. The cherry tomatoes should begin to pop under the broiler.
When ready, remove the baked halibut and vegetables from the oven.