Remove the outer husk and threads of the corn cobs, then carefully slice down the outside of the cob with a knife, as close to the core as possible, to remove the kernels. Set aside.
Heat the oil in a frying pan over medium heat. Add the ginger, garlic, chillies, and minced shallots and fry, stirring for 10 minutes. Blend to a medium fine paste in a food processor or mortar and pestle with the scallions and lime leaves. Mix the spice paste with the corn kernels in a bowl and add the coriander, cumin, salt, pepper and eggs. Stir well to combine then add cornstarch.
Fill a wok 1/3 full with oil. Heat the oil to 350 F or until shimmering. Carefully drop a small spoonful of the batter into the hot oil - it should settle into a rough circular shape. Repeat to make 6-8 fritters, without overcrowding the pan. Fry until golden brown, about 4 minutes.
Transfer to tray a tray lined with paper towel and let drain. Repeat to use up the mixture. Serve immediately with sambal or Sriracha.