Fill a pot with about 1 inch of water and set a steamer basket inside, making sure the water sits just below the basket. Cover and bring the water to a boil over medium-high heat.
Add the broccoli to the steamer basket and steam for 5 minutes, until bright green. Take care not to overcook.
Meanwhile, make an ice bath: add 4 cups ice to a large mixing bowl and cover with water. Using a slotted spoon, transfer the steamed broccoli to the ice bath and let sit for 5 minutes to stop the cooking.
Make the tahini dressing: in a bowl, whisk together all the dressing ingredients (tahini through cumin) until well blended.
Drain the broccoli in a colander, shaking off the excess water. Empty the mixing bowl and return the broccoli to it.
Add the cucumber and red onion. Pour the tahini sauce over the vegetables and stir well to coat. Season to taste with sea salt, black pepper, and cayenne.
Garnish with toasted almonds and orange and/or lemon zest, then serve.
