Cut zucchini into 1/4-inch slices (on a diagonal if they're small). Brush both sides with extra-virgin olive oil and season with salt, pepper and Parmesan (add whatever else strikes your fancy - garlic powder, Italian seasoning, rosemary or dill). The nutritionals include 2 tablespoons of Parmesan.
Set on a baking sheet in a single layer and bake in a preheated 400°F oven for 10 minutes, turning once. Cool on a wire rack.
In order to calculate Net Carbs of any whole food item, it's a simple calculation based on the Nutrition Facts panel:
Total Carbohydrates - (Minus) Dietary Fiber = (Equals) Net Carbs
For low carb products sweetened with sugar alcohols (ie: glycerin, maltitol, etc), refer to the Nutrition Facts panel of the product:
Total Carbohydrates - (Minus) Dietary Fiber - (Minus) Sugar alcohol = Net carbs
This reflects the fact that Dietary Fiber doesn't impact blood sugar levels. Sugar alcohols also have a negligible impact on blood sugar, they too are subtracted from total carbs to yield the Net Carb count.