Indian-Style Chicken Sandwiches

1 cup plain non-fat yogurt
1 teaspoon curry powder
1/4 teaspoon cayenne
1 clove garlic, pressed or minced
4 skinned and boned chicken breast halves rinsed and patted dry
2 Tablespoons chopped fresh or dry mint leaves
1/2 teaspoon cumin seed
1 loaf (1 lb.) frozen whole-wheat or white bread dough thawed
2 Tablespoons salad oil
1 small cucumber, peeled and thinly sliced
Fresh mint sprigs
Salt and pepper

In a bowl, mix 1/3 cup yogurt, curry powder, cayenne, and garlic with chicken to coat. Mix 2/3 cup yogurt, chopped mint, and cumin. If made ahead, cover both and chill up to 24 hours. Start gas grill. On a flour board, divide dough into 4 equal pieces and shape each into a ball. Roll out each ball into a 5 to 6 inch-wide round. Brush top with oil and place, oil side down, onto a piece of foil (about 10 by 12 in.). Lightly brush top with oil. With your hands, flatten round to 1/8 inch thick and 7 to 8 inches wide. Let stand, uncovered, at room temperature until slightly puffy, 15 to 25 minutes. Transport rounds (with foil) in a single layer on 12 by 15 inch baking sheet. When grill is medium hot, lift chicken from marinade and place on grill. Cook, turning once, until chicken is white in thickest part, about 10 to 12 minutes total. Remove from grill and keep warm. Turn grill to medium, lift foil supporting a bread round; flip over to put dough onto grill. Peel off and discard foil. Repeat with remaining dough.
When dough is golden on bottom, 2 to 3 minutes, turn over with a wide spatula; cook until bottom is golden but still pliable, 2 to 3 minutes longer. Transfer chicken, bread, cucumber, and yogurt sauce to a platter. To eat, place chicken in a warm bread round; add yogurt sauce, cucumber, mint sprigs, and salt and pepper to taste; fold bread over to enclose.