Place chicken in a bowl, add ginger-garlic paste, chaat masala, black salt, salt, red chilli paste and mix well. Set aside to marinate for ten to fifteen minutes.
Add gram flour to the marinated chicken and mix well.
Heat one tablespoon oil in a non-stick pan, add marinated chicken pieces and mix well. Cook on high heat, sprinkling a little water from time to time to avoid burning, till the chicken is fully done. Remove from heat and set aside.
Break the eggs in a bowl, add the salt and beat well.
Heat one teaspoon oil in another non-stick pan, add a quarter portion of beaten eggs and place a roti on it. When the egg is cooked, clip the roti with the cooked egg and drizzle one teaspoon all around and cook for half a minute. Prepare other rotis similarly.
Place each roasted roti on a plate, the egg side facing downwards. Place some chicken and some onion on it, sprinkle chaat masala and half tablespoon coriander leaves. Fold to make a roll.
Arrange the rolls on a serving plate, and serve garnished with onion and coriander leaves.