Make the bara dough: In a medium bowl, whisk together the flour, yeast, sugar, turmeric, and salt. Stir in 3/4 cup (180 ml) warm water until a sticky, soft dough forms. Add 1 to 2 tablespoons (15 to 30 ml) more water only if dry flour remains. Cover the bowl and let the dough rise in a warm spot for 30 to 35 minutes, until puffy.
Meanwhile, make the curried chickpeas: Heat 1 tablespoon (15 ml) oil in a medium saucepan over medium heat. Add the onion and cook for 4 to 5 minutes, stirring occasionally, until softened. Add the garlic, curry powder, cumin, and turmeric. Stir for 30 seconds, until fragrant.
Add the chickpeas, water, salt, and black pepper. Bring to a gentle simmer. Cook uncovered for 10 to 12 minutes, stirring occasionally and lightly crushing some chickpeas against the side of the pan. The filling should be thick and spoonable, not soupy. Taste and add more salt if needed. Keep warm on low heat.
In a small bowl, stir the tamarind chutney or concentrate with 2 tablespoons (30 ml) warm water to make a drizzleable sauce. If using concentrate, add a small pinch of sugar to taste if it is very tart.
Heat 1/2 inch (1.25 cm) of oil in a deep skillet over medium-high heat until it reaches 350°F (175°C). Line a plate with paper towels. Oil your hands lightly, then gently divide the risen dough into 8 portions. Stretch each portion into a thin, uneven round about 4 inches (10 cm) wide; do not worry if the shapes are imperfect.
Fry 2 or 3 dough rounds at a time for 45 to 60 seconds per side, until puffed, lightly golden, and cooked through. Adjust the heat as needed so the bara sizzles steadily without browning too quickly. Transfer to the lined plate and repeat with the remaining dough.
To assemble, place 2 warm bara together for each serving. Spoon curried chickpeas over one bara, drizzle with tamarind sauce, and add cucumber, cilantro, and hot pepper sauce if desired. Fold the second bara over the filling and serve right away.