Combine salmon, bell peppers, and onion in a bowl. Season with salt and pepper. Shape by hand into patties, as you would a hamburger. In a separate bowl, combine cornmeal and flour. Roll salmon patties in the cornmeal mixture.

Heat about 1-inch of oil in a large, heavy skillet to 340 degrees F. Carefully place patties, in batches as necessary, in the hot oil and fry for 3 minutes on each side or until golden brown. Drain patties on paper towels. Serve with ketchup and/or hot sauce, if desired.