Dip squash slices in egg, then breadcrumbs, then fry in oil until golden and cooked completely. Remove to a paper towel-lined pan to cool. Season with salt.
Roast peppers over a gas burner, on an outdoor grill, or in the broiler until charred. Peel and seed them, then drizzle with a little olive oil. Season with salt, pepper, oregano, and garlic (optional).

To assemble the “grinder” sandwich:
Cut the ciabatta in half lengthwise and drizzle with some olive oil and balsamic glaze. Top with squash slices, fresh mozzarella, roasted peppers, and arugula leaves. Close the sandwich, press a bit, then enjoy! Wrap well and refrigerate if you prefer to make it ahead.