Start by using a sharp knife to cut the zucchini lengthwise in half. Then, use a spoon to scoop out the zucchini centers, leaving a ¼-inch thick shell. Be sure to reserve the zucchini flesh, in a bowl to use for the filling. Next, cook the zucchini boats on a microwave-safe plate, for about 2 minutes in the microwave.
After that, dice the reserved zucchini flesh and place it in a microwave-safe bowl. Add in the olive oil, diced tomato, garlic, and thyme leaves. Stir well to combine. Cook on high in the microwave for 2-3 minutes until tender. Make sure to stir halfway through cooking.
Then stir in the breadcrumbs and parmesan cheese into the vegetable mixture, season with salt, stir again to combine well.
Proceed to pile equal amounts of filling onto each of your zucchini boats. Arrange the zucchini in a microwave safe baking dish with the stem ends towards the edge of the pan.
Put the zucchini back in the microwave and cook, covered, on high for 2-3 minutes until hot. Let stand loosely covered for 2 minutes to cool slightly.