Combine all of the dressing ingredients in a jar with lid. Cover and shake to combine.
Refrigerate the dressing until ready to use.
Place a large pot of water with 2 pinches of salt on the stove and bring to a boil.
While the water is coming up to a boil, run the summer squash through the spiralizer using the flat blade insert. With all the spiralized squash laid out on a cutting board, use a large knife to roughly cut into thirds. We're just looking to shorten the "noodles" some.
Add the spiralized squash to the boiling water and cook for about 5 minutes, until tender.
Transfer the squash to a colander and rinse with cold water. Remove as much water as you can from the squash. Leave the squash in the colander while you prepare the remaining ingredients.
Add the squash, bell pepper, red onion, salami, olives, and mozzarella (if using) to a large bowl.
Pour about half the dressing over the salad and toss the ingredients to combine. Add more dressing as desired.
Store the salad in the fridge until ready to serve.