For the tempeh: In a small bowl, whisk together the sesame oils, soy sauce, vinegar, mirin, ginger, and garlic. In a large saute pan, arrange the tempeh in a single layer, pour the marinade over it, and bring it to a boil over high. Reduce the heat to low, cover the pan, and simmer for 20 minutes. Uncover, raise the heat, and cook the tempeh until the pan is nearly dry. Remove from the heat. (At this point the tempeh can be refrigerated, tightly wrapped, for 1 week.)
For the peanut sauce: In a blender, combine the peanut butter, maple syrup, soy sauce, vinegar, ginger, garlic, and cayenne. Puree, adding enough hot water to form a creamy, pourable sauce.
Serve the tempeh over white rice with the peanut sauce and garnish with the radish, scallion, and cilantro.