Prepare zucchini. Prepare your zucchini by trimming off the stem end. Then cut each zucchini in half length-wise. Use a measuring spoon (teaspoon) to hollow out the zucchini forming a boat.
Make the filling. Add bell peppers, taco seasoning, salt, and ¼ cup of water to the ground beef. Continue to cook until vegetables are softened and water has been absorbed.
CAN YOU MAKE ZUCCHINI BOATS AHEAD OF TIME? Yes, you can make these up to 2 days ahead of time. Follow all of the instructions up to step 6, filling the boats. After each one is stuffed cover tightly (or store in an airtight container and put the back in the casserole dish before baking). When you are ready to cook them just sprinkle the cheese on top and bake. This may take slightly longer since they will be cold but just keep an eye on them and use a fork to test when the zucchini has softened. Alternatively I bake mine and then keep the leftovers in the refrigerator to heat up for a quick lunch during the week. They reheat great!