In a saucepan cook the onion in the oil over moderately low heat, stirring occasionally, until it is softened, add the flour, and cook the mixture, stirring, for 1 minute. Stir in the broth, bring the mixture to a boil, stirring, and add the cucumber. Bring the mixture to a blender, and puree it with the tofu and the lemon juice until the mixture is smooth. Bring the remaining broth mixture in the pan to a boil, add the scallops, and simmer them, stirring, for 3 minutes, or until they are just firm. Reduce the heat to moderately low, stir in the tofu mixture, the dill, and salt and pepper to taste, and heat the chowder, stirring, until it is hot, but do not let it boil. Makes about 3 cups, serving 2. Gourmet June 1992