In a mixing bowl, combine dry ingredients. (flour, corn flour, ground Tostitos, baking powder, baking soda, and salt.
In a separate mixing bowl, combine the egg yolks and buttermilk and whisk in the melted butter. Add the onion, bell peppers, garlic, green onion, cilantro, shrimp and corn kernels.
Using an electric mixer or hand held mixer, whip the egg whites and sugar together to stiff peaks.
Mix the dry and wet ingredients and then fold 1/3 of the egg whites in to lighten the batter and then fold that mixture into the remaining 2/3 of the egg whites.
Heat the vegetable oil to 325 degrees and spoon in about 2 Tablespoons of batter into the broken Tostitos and gently roll it over and drop into the frying oil. Repeat several times. After about 30 seconds, turn the fritters over and keep moving them around in the oil until they are golden brown all around. Remove from the oil and drain on paper towels.