Preheat oven to 400°F. Brush uncut sides of pita rounds with 1 tablespoon oil, and sprinkle with 1/4 teaspoon salt and 1/4 teaspoon pepper. Place directly on oven rack, and bake at 400°F until crispy, 5 to 6 minutes. Cool slightly, about 5 minutes. Slice pitas into thin triangles. Set aside.
Using a Y-shaped peeler, peel thin strips from zucchini to measure about 1 cup. (Reserve remaining zucchini for another use.) Toss together zucchini strips and 1 1/2 teaspoons chipotle chiles; let stand at room temperature 10 minutes.
Whisk together lime juice and remaining 1 tablespoon chipotle chiles in a small bowl. Gradually whisk in remaining 3 tablespoons oil. Toss together lettuce, chickpeas, tomatoes, and dressing. Season with remaining 1/4 teaspoon salt and remaining 1/4 teaspoon pepper. Divide among 4 bowls. Top with zucchini strip mixture, pita triangles, sour cream, pumpkin seeds, and scallions.