zest of one lemon

Sauce:
1/3 cup / 80 ml extra virgin olive oil, plus more for the pan
1 1/2 teaspoons crushed red pepper flakes
scant 3/4 teaspoon fine grain sea salt
4 medium cloves of garlic, finely chopped
1 28-ounce can crushed red tomatoes
1 14-ounce can crushed red tomatoes

Filling:
1 15-ounce container ricotta cheese
1 egg, beaten
1/4 teaspoon fine grain sea salt
1 cup / ~5 oz grated mozzarella
1 bunch of chives, minced

25-30 jumbo dried pasta shells