Place baking sheet in oven and heat to 450°F. Cut zucchini in half lengthwise and hollow out each  half. Brush cut sides with 1 teaspoon oil, then place, cut sides down, on heated baking sheet. Roast 5 minutes.

Meanwhile, heat 2 teaspoons olive oil in large skillet on medium-high. Add sausage and cook for 3 to 4 minutes. Drain and transfer to Bowl.

Add green onion to sausage.

Fold in cheese and if you choose too cilantro. Divide sausage mixture among zucchini halves and roast  8 to 10 minutes more. Sprinkle with cilantro if desired.