This combination of summertime vegetables works well; substitute others in season.
Toss together the couscous and 1/4 tsp salt in a bowl. Drizzle in 1 tsp of the oil, and stir until the couscous is evenly coated. Pour the boiling stock over the couscous, cover the bowl tightly, and set it aside for about 10 minutes. Grind together the cumin, turmeric, coriander, fennel, caraway, and cayenne in a spice grinder or mortar and pestle; set aside.
Set a wok over medium-high heat, pour the remaining oil around the rim, and tilt the pan to coat the sides. Add the onion and stir-fry for 2 to 3 minutes, until translucent. Stir in the garlic and kohlrabi and continue stir-frying for 2 to 3 minutes. Gradually add the bell pepper, beans, and zucchini, stirring all the while.
Add the spice mixture and cook for about 1 minute longer, stirring constantly. Stir in the tomato and stock. Bring the liquid just to a simmer, cover the wok tightly, and cook for 5 to 10 minutes, until the vegetables are just tender. Add salt to taste. Fluff the couscous and mound it on a platter or individual plates. Serve the vegetables on top, garnished with the cilantro, currants, and pistachios.