In a mixing bowl, combine the prawns with lime juice, salt, ginger garlic paste, and red chilli powder. Ensure the prawns are well coated. Let them marinate for 15 minutes.
In a separate large bowl, prepare the batter. Mix together besan, corn flour, red chilli powder, cumin, turmeric, chaat masala, and water. Adjust the water quantity to achieve a thick batter consistency.
Gently fold the marinated prawns into the prepared batter, ensuring they are thoroughly coated.
Heat oil in a deep frying pot over medium-high heat. Once the oil reaches a temperature of about 350°F (175°C), carefully add the prawns in batches. Fry each batch for approximately 2 minutes, until the prawns are fully cooked and have a golden, crispy exterior.
As each batch is done, use a slotted spoon to transfer the prawns to a wire rack to drain excess oil.
Serve the prawns koliwada hot, garnished with slices of red onion, chopped cilantro, and green chutney. Don’t forget to squeeze some fresh lime over the prawns for that extra zing.