Beans: Drain soaking water off the beans and place beans in a large pot with garlic, cumin and 3 c water. Bring to boil, then simmer over low heat, covered, for 50-60 minutes. Or pressure-cook in 2 c of water for 45 minutes.
Vegetables: Heat oil in large skillet. Add onion, salt and garlic; saute until soft.
Add pepper, zucchini, cumin and oregano and saute 5 more minutes.
Add cooked beans to the vegetables with tomato sauce and 1/4 cup water. Check taste and add salt if needed.
Polenta: In separate pot, bring 3 c water to a boil. Add salt an boil. Slowly add polenta, stirring continuously with a whisk. Lower heat and continue stirring in clockwise motion with a wooden spoon for 10-15 minutes or until mixture can hold the spoon upright on its own.
Preheat oven to 350. In a lightly oiled casserole dish, spread the bean & vegetable mixture across the bottom. Spread the polenta on top. Sprinkle with parmesan cheese.
Bake, covered, for 25 minutes at 350. Remove coer and bake 5 minutes more at 400.