Bring water, sorghum, 1 teaspoon oil, and ½ teaspoon salt to a boil in a medium saucepan over high heat. Reduce heat to low, cover, and simmer 80-85 minutes until grains are tender and water has been absorbed. Remove from heat, fluff with a fork, and let cool completely.
Line a baking sheet with parchment paper.
Transfer cooked sorghum to a food processor and pulse until the grains are chopped and start to stick together, about 20 one-second pulses; transfer to a large bowl.
Heat 1 tablespoon oil in a skillet over medium until shimmering. Add shallot and cook until softened, about 2 minutes. Stir in arugula and carrots and cook until arugula is wilted, about 2 minutes. Stir in garlic, curry powder, and 1 teaspoon salt, cook until fragrant, about 30 seconds; season with pepper. Add arugula mixture to bowl with sorghum and toss to combine; wipe out empty skillet.
Add ¼ cup yogurt, egg, and cilantro to sorghum-arugula mixture and stir to combine. Divide mixture into 8 portions (¼ cup each) and pack into firm ½-inch-thick cakes. Transfer cakes to prepared sheet and chill until firm, about 30 minutes or up to overnight.