Heat the oven to 400 F. Put a 10-inch ovenproof skillet on the stove so it is ready when you need it.

Add the olive oil to the skillet and warm it over medium heat.

Add the onion and zucchini to the skillet. Cook for 5 minutes, stirring a few times, until the onion softens and the zucchini looks glossy.

Add the sliced garlic to the skillet. Cook for 30 seconds, stirring, until it smells fragrant.

Stir the tomato paste into the vegetables. Cook for 1 minute so it darkens slightly and loses its raw taste.

Pour the crushed tomatoes and water into the skillet. Stir well and scrape the bottom of the pan so nothing is stuck there.

Raise the heat to medium-high and bring the tomato mixture to a steady simmer.

Add the dry orzo to the skillet. Stir well so the pasta is evenly spread through the liquid.

Lower the heat to medium-low. Let the orzo simmer for 8 minutes, stirring every 1 to 2 minutes so it does not stick.

Check the skillet. If the mixture looks dry before the orzo is almost tender, stir in 2 to 4 tablespoons of extra water.

Keep cooking until the orzo is nearly tender and the sauce looks a little loose. It should still have some movement because it will thicken more in the oven.

Taste the sauce and add salt if it needs it. Smooth the top of the orzo with the back of a spoon.