Wash the zucchini and cut off the ends. Use a vegetable peeler / potato peeling knife to peel the zucchini lengthways into strips. This is how the ribbon noodles are made. Peel to the core. The rest can either be thrown away or cut into small pieces and added to the sauce. Put the ribbon noodles in a sieve and sprinkle with salt. This removes the water from the zucchini. Peel the onion and cut into small pieces. After a while, pat the ribbon noodles dry with a little kitchen towel.
Heat some oil in a pan and fry the zucchini strips with the onions. Add the tomatoes and the diced feta. Add the pressed garlic (or garlic powder) and other spices. Let the whole thing simmer briefly, otherwise the zucchini will be too soft.