Rowdy Rooster Fried Chicken Sandwiches

Ingredient:

• 10 (about 3 1/2 pounds total) boneless, skinless chicken thighs
• 1/4 cup plus 3 tablespoons (3 1/2 ounces) white vinegar
• 6 tablespoons (4 ounces) ginger-garlic paste, divided
• 5 tablespoons kosher salt, divided
• 1 1/4 cups (10 ounces) plain whole-milk yogurt
• 1/4 cup chili powder
• 2 tablespoons plus 2 teaspoons garam masala
• 1 tablespoon ground turmeric
• 2 cups (about 8 1/2 ounces) all-purpose flour
• 1 1/4 cups (about 6 3/4 ounces) cornstarch
• 2 tablespoons black pepper
• 3 cups roughly chopped fresh mint
• 1/2 cup roughly chopped red onion (from 1 small [2 ounces] onion)
• 1/4 cup water, plus up to 1/3 cup more water as needed
• 1 tablespoon coarsely chopped (and seeded, if desired) fresh Indian green chiles or Thai green chiles (from 4 medium [1/2 ounces total] chiles)
• 2 teaspoons coarsely chopped fresh ginger
• 6 cups roughly chopped fresh cilantro, divided
• 1 tablespoon plus 1 teaspoon fresh lemon juice (from 1 medium [4 ounces] lemon)
• 1 1/2 teaspoons granulated sugar
• 1 teaspoon kosher salt
• 1 teaspoon amchur (unripe mango powder)
• 1/2 teaspoon hot chili powder
• 1/2 teaspoon fine sea salt
• 1 medium-size (9 ounces) red onion, thinly sliced crosswise into half-moons
• 1 1/2 cups (12 ounces) plain whole-milk yogurt
• 1 (5-ounce) bunch scallions, trimmed and finely chopped (1 1/3 cups)
• Peanut oil
• 2 cups (16 ounces) salted butter
• 1/3 cup chaat masala
• 1/3 cup Kashmiri chili powder
• 10 kaiser rolls or brioche-style hamburger buns, split