Preheat broiler. Place jalapeño halves on a foil-lined baking sheet. Drizzle with 1 Tbsp of the olive oil; toss to coat. Place jalapeños skin-side up. Broil 4 to 5 inches from the heat until lightly charred, about 5 minutes. Let cool until easy to handle. Meanwhile, cut the chicken breasts lengthwise into 1⁄4-inch-thick strips. Drizzle chicken with the remaining 1 Tbsp olive oil and sprinkle with the garam masala powder and the salt; toss to coat evenly. Thread chicken onto wooden skewers, using 1 or 2 pieces per skewer. Preheat a grill pan over medium-high heat. Grill chicken for 5 to 6 minutes or until cooked through (165°F), turning once. Meanwhile, finely chop the jalapeños.In a small bowl, combine the jalapeños, yogurt, cilantro, and cumin. Season to taste with salt and black pepper. Serve the chicken skewers with the jalapeño dip.