In a large cast-iron skillet or casserole, heat 1 tablespoon of olive oil over medium-high heat and sauté the onion until translucent. Add the eggplant and continue to cook, stirring occasionally, until the eggplant has begun to soften, about five minutes. Toss in the pepper and the squash and cook until tender. Add the garlic, tomatoes, balsamic, red pepper, and sugar. Add salt to taste. Turn the heat down to medium-low and allow to reduce until some of the tomatoes’ acidity has softened, and the overall flavor of the sauce is to your liking. Stir in the cooked orzo and the cooking liquid until everything is well incorporated. Smooth the surface of the orzo mixture with the back of your spatula, and cover evenly with the cheeses. Place the skillet/casserole in the oven for five minutes or so until the cheese has melted and begun to brown.