Preheat oven to 350°. Gently roll chickpeas in batches between clean kitchen towels to blot dry and slough off papery skins; discard skins. Divide chickpeas between 2 rimmed baking sheets. To each pan, add 3 tbsp. oil, 1 tsp. garam masala, and 1/2 tsp. salt and mix well to coat. Spread in an even layer.
Bake, stirring occasionally, until chickpeas are crisp all the way through, 75 to 80 minutes. Add more salt to taste if you like. Serve warm or at room temperature.