Combine the marinade ingredients and mix well: yogurt, garlic, cumin, garam masala, coriander, turmeric, salt, and pepper. Pour mixture over the chicken in a resealable plastic bag, and rub marinade into the meat. Marinate for at least one hour, and up to 24 hours.
When ready to prepare the salads: Place chicken on grill, discarding any extra marinade. Cook for approximately 5-6 minutes per side, turning once, until chicken is done. Meanwhile, skewer tomatoes or place in a grill basket and cook until slightly charred, about 5 minutes, stirring or turning periodically.
Allow chicken and tomatoes to cool.
Meanwhile, combine dressing ingredients and mix well: the remaining plain yogurt, cumin, garam masala, salt, cilantro, white wine vinegar, olive oil, and cayenne pepper.
In a large bowl, combine the romaine lettuce, cucumber, and chickpeas.
Chop chicken when cool enough to handle, and add chopped chicken and tomatoes to the salad.
Toss with dressing until all ingredients are mixed well.