Sprinkle eggplant pieces with salt & set aside for 6 to 8 minutes. Meanwhile in a large skillet, saute onions & garlic in the oil until golden, stirring & ensuring that it's not scorching. Add all the spices & peppers & stir-fry a couple of minutes. Squeeze eggplant pieces to get rid of excess moisture. Dump the pieces into the pot. Stir until they become limp & slightly golden. Add more oil if necessary Add the potatoes & let them brown on all sides. When potatoes are somewhat tender, but still fork resistant, add tomatoes, paste & 1 1/2 c water. Stir, bring to a boil, reduce heat & simmer until vegetables are tender but not mushy. The sauce should be thick, like syrup. If too thin, simmer a little longer. Serve over rice.