Smoked Eggplant and Yogurt

1 medium eggplant, peeled and chopped
1/2 cup lightly salted water
1 1/2 cups plain regular or low−fat yogurt
1 small bunch green onions, diced
1/2 bunch cilantro, diced
1 teaspoon ground black pepper
salt to taste
1/4 teaspoon paprika
1 piece charcoal
1 − 5x5 inch piece aluminum foil
1 tablespoon margarine or shortening