For the smoky tahini dressing: In a blender, blend together the tahini, lemon juice, paprika, cumin, garlic, 1/2 teaspoon salt and 1/2 cup cold water until creamy.
For the sesame rice: Bring a medium pot of water to a boil, add the rice and 1/2 teaspoon salt, and reduce the heat to medium-low. Simmer, uncovered, until al dente, about 15 minutes; drain. Stir in the sesame seeds and sesame oil.
For the warm Brussels sprout-shiitake slaw: Meanwhile, in a large skillet, heat 1 tablespoon olive oil over medium-high heat. Add the mushrooms and cook, stirring occasionally, until softened, about 5 minutes. Add the remaining tablespoon olive oil, Brussels sprouts and the date; cook, stirring occasionally, until tender and slightly charred, about 5 minutes. Season to taste with salt. Divide the rice among 4 serving bowls, and top each with some of the warm Brussels sprouts-slaw and tahini dressing.