Trim scallions and thinly slice the whites to yield between 1/2 and 1/3 cup. Slice enough greens thinly on the diagonal to yield about 1½ cups. Heat 1½ tsp oil in a medium skillet over medium heat. Add the scallion whites and cook, stirring, until softened, about 2 minutes. Add another 1½ tsp oil to the pan, and then the curry powder, cumin and ½ tsp of salt. Cook, stirring, until combined and fragrant, about 15 seconds. Remove from heat. Whisk the flour, sugar, baking powder and soda, and 1 tsp of salt in a medium bowl.
In a 2 qt saucepan, bring the lentils and 1½ cups water to a boil over medium-high heat. Reduce to a simmer and cook, stirring occasionally, until tender. Drain through a sieve positioned over a medium sized bowl. Reserve ½ C of the cooking liquid.
Transfer the lentils to a medium sized bowl and mash with a fork until smooth, adding a little of the reserved cooking liquid if necessary. Add 1 cup of the yogurt, the egg and ¼ C oil, and stir to combine. Add the dry ingredients, cooked scallion whites and raw greens, stir to combine.
In a small bowl, stir remaining ½ C yogurt with the lime juice and season with a little pepper. Meanwhile, lightly oil a nonstick griddle and heat over medium-low heat.
Working in batches, pour about ⅓ C of the batter onto the griddle, and spread with the back of a spoon until the pancake is about 4” in diameter. Repeat to make more pancakes, cook, undisturbed, until the top is very bubbly and partially set and edges are browned. Flip with a spatula and continue cooking until the second side is nicely browned. Repeat with remaining batter. Cut pancakes into wedges if large, and serve with the lime yogurt.