To prepare sauce, place first 8 ingredients in a food processor; process until smooth. Cover and chill until ready to serve.
To prepare cakes, combine cornmeal and next 6 ingredients (through 1/4 teaspoon red pepper) in a large bowl; add buttermilk, 1 tablespoon of chives, and egg, stirring with a whisk until blended. Fold in corn and scallops.
Heat a nonstick griddle or large nonstick skillet over medium-high heat. Coat pan with cooking spray. Spoon batter by heaping tablespoons onto hot pan. Turn johnnycakes over when edges begin to brown (about 2 minutes). Cook an additional 2 minutes or until lightly browned. Remove johnnycakes from pan; cover and keep warm. Repeat procedure with cooking spray and remaining batter. Serve warm with sauce.