Preheat the oven to 350 degrees F (175 degrees C). Butter a 2-quart baking dish.
Bring water to a boil in a large saucepan, and sprinkle in rice. Stir, reduce heat to low, and simmer rice until it is half-cooked about 5 minutes. Drain rice, and set aside.
Melt butter in a large skillet over medium heat, and cook and stir onions until translucent but not browned, about 8 minutes. Mix cooked onions and butter in the skillet with rice; stir in half-and-half, salt, and 1 3/4 cup of Swiss cheese. Transfer mixture to the prepared baking dish, and sprinkle remaining 1/4 cup Swiss cheese over top.
Bake uncovered in the preheated oven until rice is tender and top is lightly browned, about 1 hour.
