Slice top and bottom ends off orange, just enough to expose flesh. Slicing top to bottom, cut away peel and white pith. Hold orange over a small bowl; cut along membranes and release segments into bowl, catching the juice in the bowl. When you’ve finished cutting, squeeze orange to release remaining juice into bowl. Transfer segments to a large bowl; pour juice into a blender (you’ll have about 2 tablespoons).
Place 1 tablespoon of the grapeseed oil, ginger, and garlic in a small skillet. Turn heat to medium-low. When mixture sizzles, let it cook for 30 seconds; transfer to blender. Add remaining 3 tablespoons grapeseed oil, vinegar, miso, sesame oil, and carrots to blender. Pulse to chop carrots, then let blender run to puree dressing.
Place endive, radicchio, and celery in bowl with orange. Add dressing a few tablespoons at a time and toss (you may not use it all). Divide among 4 plates; sprinkle with almonds, if desired.