In a large saucepan over medium heat, brown the rice, stirring constantly; pour it into a greased or pan-sprayed 1-1/2-quart or larger oven-safe casserole.
In the same saucepan, melt the margarine and add the onion and curry powder. Note that you might want to add a bit of tamari, Bragg's Liquid Aminos, or salt if you're using curry powder that does not contain salt.
Cook until the onion's almost transparent, about 5 minutes, and then add the spinach, tofu, and corn; cook until all are thawed, breaking up the tofu with a spoon.
When through, drain, pressing the liquid out of the vegetable/tofu mixture (or you can just squish it through your fingers, in which case, of course, cool it slightly beforehand).
Reserve this liquid and add enough hot water to it to make 2 cups. In a separate container, heat this liquid to boiling.
Stir the boiling liquid back into the vegetable/tofu mixture and bring it all to a boil.
Remove it from the heat and stir it into the rice that's in the casserole dish.
Cover and bake it at 350 degrees for about 30 minutes, or until the rice is tender and all the liquid has been absorbed.