Cook the soba noodles in a large pot of salted, boiling water according to package directions. Be sure to give them a good stir now and then, especially at the beginning, so that they don’t clump up. Drain, rinse in cold water and transfer to large bowl. Toss with 1 teaspoon sesame oil.
In the meantime, in a blender combine the olive oil, peanut butter, tea, garlic cloves, tamari or soy sauce, mirin, vinegar, honey, red pepper flakes, and juice from ¼ lime. Blend until smooth. Taste and add additional lime juice if desired. Pour the sauce over the warm noodles and toss to combine. It will look quite soupy at this point, but the sauce will get absorbed as the noodles chill. Refrigerate for at least 1 hour, but up to 24 hours. Do Ahead: The noodles can be tossed with the sauce and refrigerated for up to 24 hours.
Layer the scallions, cucumbers, spinach, mint and peanuts over the noodles. At this point, the salad can be covered again and refrigerated for an additional 4 hours, or it can be tossed together with tongs and served right away. For a picnic, divide the salad into individual serving containers, pack them in the cooler or backpack and hit the road.