Break udon in half and cook in boiling water until just tender, according to package directions, making sure not to overcook. Drain and cool under cold running water. In a food processor or blender, combine almonds, vinegar, ginger, tamari, almond butter, garlic, chili powder, and canola oil. Pulse until smooth.
Combine the udon noodles and green beans in a large bowl. Toss with the almond ginger dressing to coat.