Cut the ends off the corn and remove any dirty outer leaves, but don't shuck them. Put them in the microwave and cook on high for 4 minutes. Let them cool in the microwave while you continue with the recipe.
In a mixing bowl combine sour cream, lime zest and juice, paprika, tajin, and chili powder. Mix well. Add the pepper and feta.
Take the corn out of the microwave. When cool enough to handle, shuck the corn. Using a sharp chef's knife, cut straight down the cobs all around until all the kernals have been cut off. Add the corn kernals to the sour cream mixture. Gently stir the salsa together so that all of the corn is coated. Fold in the cilantro if using.
If possible, chill for half an hour to allow flavors to marry. Serve with chips.