Heat 1 tablespoon butter in a small saucepan over medium heat. Stir in the rice and 1/4 teaspoon curry powder. Add 1 1/4 cups water, 1/2 teaspoon salt and a few grinds of pepper. Bring to a boil, then reduce the heat to low; cover and cook until the liquid is absorbed, 15 minutes. Let stand off the heat, covered, 5 minutes.
Meanwhile, heat the remaining 1 tablespoon butter in another small saucepan over medium-high heat. Add half of the red onion; cook, stirring, until browned, 3 to 4 minutes. Stir in the garlic and remaining 1 1/2 teaspoons curry powder, then add the chickpeas, 1 cup water, a pinch of salt and a few grinds of pepper. Bring to a boil, then reduce to a simmer. Mash some of the chickpeas against the side of the pan with the back of a spoon. Simmer until thickened, 13 to 15 minutes. Season with salt and pepper.
Meanwhile, dice the tomatoes and cucumbers and combine in a bowl with the remaining red onion; season with salt. Let sit 5 minutes, then drain off any liquid. Add the lemon juice and more salt, if needed.
Warm the tortillas as the label directs. Top with the rice, forming a log in the center, then top with the chickpeas. Add 2 tablespoons yogurt and 2 tablespoons of the tomato-cucumber salsa to each tortilla. Fold in the sides of the tortillas and roll up. Serve with the remaining yogurt and salsa.