Place the cauliflower in a large pot, cover with water (make sure veggies are submerged), and bring to a boil.
Reduce heat to low, cover, and simmer for about 22 minutes, until the cauliflower is very soft. Drain and set aside to cool.
Once cooled, in batches put 1/3 to 1/2 of the cauliflower in a dish towel and squeeze out as much excess water as possible then place in a large bowl. Repeat with the remaining cauliflower until all of it is well drained and squeezed of all liquid so the dough isn’t too sticky.
Add the flour and salt into the bowl with the mashed cauliflower and mix with a fork at first, then using your hands to fold and squeeze everything together into a dough.
Dust a work surface with flour, then separate the dough into 8 equal pieces, about 2 1/2 ounces each. One at a time, roll each ball into a ½-inch-thick rope 10 inches long and set aside. Continue until all the dough is used up.
Next, cut each rope into 13 equal sized (gnocchi-like) pieces, slightly nudging the pieces apart so they’re not touching. You should get about 108 pieces total. If at any point the dough becomes too sticky to work with, add flour to your hands.
In two batches, liberally mist a large a skillet with nonstick oil spray and warm over medium heat. Place half of the gnocchi on the hot skillet (if the pieces stick together just slice them apart in the skillet using the spatula). Do not overcrowd the pan; you’ll need to cook the gnocchi in two batches.
Let the gnocchi sit in the hot pan undisturbed for 2 minutes, then gently flip using a spoon or tongs, being careful not to squish them. Sprinkle salt over the tops and continue to cook for another 2 to 4 minutes or until desired doneness.
Set aside and repeat with remaining gnocchi, then add everything back to the skillet and pour the marinara over everything, give a stir and serve topped with optional grated cheese.