In a large skillet, heat the oil. Add the scallions, ginger and jalapeño and cook over moderate heat, stirring, until fragrant, about 1 minute. Add the peas and cook, stirring occasionally, until tender, about 3 minutes.
Transfer the pea mixture to a food processor and let cool slightly. Add the miso and 1/4 cup of water and puree until smooth. Spoon the spread into a bowl.