Pre-heat your oven to 425 degrees.
Arrange the cauliflower on a large baking sheet in an even layer. (I like to line my baking sheet with foil for easy cleaning, but you do you.) Drizzle with olive oil and season generously with salt and pepper. Toss to coat. Roast for 20 minutes until tender and lightly browned. Set aside until ready to use.
Place all the ingredients for the dressing in a small bowl. Whisk to combine. Let stand for 10-15 minutes to allow all the flavors to mingle.
Moving on the soba noodles! Bring about 8 cups of water to a boil. Add the noodles and cook for 3-5 minutes until just tender. (The cooking time will vary based on your noodles. Check the directions on the package, but start testing your noodles about 1 minute before the suggested cooking time. They can overcook quickly!) Strain the soba noodles and rinse with cold water.
Transfer the soba noodles to a large bowl. Add the roasted cauliflower, cilantro, hemp/sesame seeds and ginger-scallion mixture. Toss to combine. (I actually find it easiest to do this with my hands…)
Squeeze the lime over your soba noodles before serving.