Preheat the oven to 375°F. Halve squash lengthwise and use a spoon to scoop out seeds and discard. Place squash cut-side down in a 9×13-inch baking dish. Pour 1 cup water into the dish and roast until squash shells are tender when pressed with your finger, about 30 minutes. Let sit until cool enough to handle. Leave oven on.
Meanwhile, puree almonds in a blender and pour tomatoes into a strainer set over a bowl. Set tomatoes aside and add juice to the almond puree in blender, add curry powder and ¼ tsp of the crushed celery seed and blend until smooth.
Rake a fork back and forth across squash to remove flesh in strands, keeping shells intact. Transfer squash to a bowl and toss with remaining 1/8 tsp crushed celery seed. Return shells cut-side up to the baking dish. Spoon one-third of the squash into shells, dividing evenly. Top with half of the tomatoes and half of the greens, then drizzle with about one-third of the almond sauce. Repeat the layering. Top with remaining squash and sauce. Roast until filling is heated through and greens have wilted, about 15 minutes.