In a food processor, combine the enchilada sauce, 1/4 cup of the cilantro, the jalapeños and 2 of the green onions. Cover and process for 20 to 30 seconds or until smooth. Pour in to a small container and refrigerate.
Rinse the food processor bowl. Place 1 cup of the corn in the food processor. Cover and process for 20 to 30 seconds or until smooth. Add the butter, sugar and a pinch of the salt. Cover and process for 30 seconds or until smooth and well combined.
Add the masa harina and the flour. Cover and pulse for 4 or 5 times or just until moistened. Stir in the remaining 1/2 cup corn.
Turn the dough onto a work surface lightly coated with masa harina. Roll the dough into a log. Cut in 8 portions. Pat each portion into a 3-inch round. Place on an ungreased cookie sheet. Bake the cakes for 15 minutes or until the bottom is a deep golden brown. Turn the cakes over and bake for 5 minutes longer or until golden brown.
Meanwhile, chop the remaining 1/4 cup cilantro. In a medium bowl, mix the cilantro, tomatoes, bell pepper, lime peel, lime juice and the remaining salt.
To serve, pour the chilled green sauce on a serving platter. Top with the hot corn cakes. Spoon the tomato mixture over each corn cake. Drizzle with the sour cream.