Wash the spinach well. Remove the coarse stalks from chard; dry the leaves thoroughly and chop rather fine. Using a heavy skillet, cook spinach in 2 tablespoons olive oil over medium heat until just wilted. Drain and put into a large bowl.
Wash, dry, trim and dice the unpeeled zucchini; add about 4 more tablespoons of olive oil to the skillet. Saute' the zucchini, tossing well until just tender.
Add zucchini to the spinach and chard, season with salt to taste, and mix in the already cooked rice and garlic. Combine well. Transfer to a well-oiled, heavy 2 quart baking dish. Spoon 3 to 4 tablespoons olive oil over the top.
Bake in a 300 oven for 20 minutes. Beat the eggs well; pour them over the vegetables mixture; sprinkle the top with bread crumbs; return to the oven and bake until the eggs are just set, about 10 to 15 minutes.
Eat warm or cold. This makes an excellent luncheon or supper dish.