Italian Veggie & Cheese Stromboli

large zucchini, sliced 1/4 inch thick

and 1/2 teaspoons Sea or Kosher salt or 3/4 teaspoon table salt

large yellow or red onion, thinly sliced

green bell pepper, thinly sliced into strips

olive oil, for sauteing

garlic, minced

roasted red pepper, thinly sliced into strips

green cayenne pepper, diced or red pepper flakes

packed cups spinach leaves

green or black olives, chopped

capers

fresh black pepper

heaping teaspoon Italian seasoning

pizza dough*

Gouda cheese, shredded

egg, lightly beaten with a teaspoon of water

poppy or sesame seeds, optional

tomato sauce, for serving