Smoked Cod Rillettes

Name: Smoked Cod Rillettes
Ingredients: 1 shallot, finely chopped; Canola oil, for cooking; 1 quart cold-smoked cod; 1 cup sour cream; 1/2 cup mayonnaise; 2 tablespoons finely chopped fresh dill; 2 tablespoons finely chopped fresh parsley; 2 tablespoons finely chopped scallion; 1 tablespoon hot sauce; 1 tablespoon freshly ground black pepper; 1 tablespoon salt, or more as needed; 1 teaspoon fermented Fresno powder (sub cayenne if unavailable); 1 teaspoon MSG, optional; Juice and zest of 2 limes, or more as needed; Juice and zest of 1 lemon, or more as needed; 1/2 preserved lemon, finely diced; Toasted crostini, for serving