Either open the clams by hand, reserving both the juice within them and the clams, or steam the clams until they just open, reserving both the broth and the clams. Put the clams on a cutting board, and chop them coarsely. Put the flour in a mixing bowl, and add to it the egg yolks, onion, red pepper, celery, garlic, jalapeño and clams, then mix to combine. Add the clam broth to the mixture, and stir until it is a thick batter running almost to loose. Make the sauce. Whisk together the ketchup, mayonnaise, hot sauce and lime juice in a medium-size bowl. Season to taste with salt and pepper. Add more mayonnaise, hot sauce or lime juice if desired. Beat the egg whites until stiff, then whisk the baking powder into the clam batter, and carefully fold the egg whites into it afterward. Heat enough oil to come up an inch or so on the sides of a large, deep frying pan until it is quite hot, approximately 350 degrees. Drop the batter by the tablespoon into the hot oil, making sure not to crowd the pan, and cook, turning once or twice, until the fritters are golden brown and crisp. Remove with a slotted spoon, and place on a warmed platter. Serve with the sauce on the side, with the scallions and wedges of lime.