In a small skillet, heat 1/4 cup plus 2 tablespoons of the oil. Add the shallot rings and cook over moderate heat, stirring a few times, until golden brown and crisp, about 3 minutes. With a slotted spoon, transfer the shallot rings to a bowl. Add the garlic to the hot oil and cook over moderately low heat, stirring a few times, until golden, about 1 minute. With a slotted spoon, transfer the garlic to the bowl. Add the ginger to the skillet and cook until fragrant, 2 minutes. Add the red pepper powder and sugar and cook, stirring, for 30 seconds. Scrape the sauce into the bowl. Stir in the fish sauce and the remaining 1 tablespoon of oil.