Cook the orzo in well salted water according to package directions.
Meanwhile, heat the olive oil for a minute or two in a 12-inch nonstick skillet over medium heat. Add the onions, garlic and a big pinch of salt and cook, stirring frequently, for fives minutes or so, until the onion is beginning to soften. Add the shredded zucchini and the thyme and raise heat to high. Cook, stirring occasionally, until the squash releases its juices and they cook off and then the squash begins to brown slightly. (Camille's recipe says to sauté "briefly," but I'm thinking that brief must mean something different to people who start their food from seed. This process takes 10 to 15 minutes when I do it.) Turn off the heat and immediately add the drained orzo, lemon juice and zest, and cheese, along with salt and pepper to taste. Stir well but gently to combine. Serve warm or at room temperature.