In a large saucepan, heat the vegetable oil. Add the ginger and cook over moderate heat until golden, about 1 minute. Add the seasoned vegetables and cook over moderately high heat until they just start to brown around the edges, about 4 minutes. Add the tomatoes and half of the cilantro, cover and cook until the vegetables are tender, about 10 minutes. Stir in the edamame and cook for 2 minutes longer. Remove from the heat. Stir in the yogurt and lemon juice and season with salt. Transfer the vegetables to bowls, garnish with the remaining cilantro and serve with the warmed pitas.