Heat the oil in a medium saucepan over medium heat. Add the onion and 1/4 teaspoon of the salt and cook, stirring occasionally, until the onion is very soft, about 7 minutes. Add the cumin, coriander, turmeric, and cinnamon, and cook, stirring, for 1 minute. Stir in the broth, increase the heat to high, and bring to a boil. Add the currants, cover, remove the pan from the heat, and let sit for 10 minutes so the currants can plump.
Return the broth to a boil over high heat. Stir in the couscous and the remaining 1/2 teaspoon salt, cover, remove from the heat, and let sit for 5 to 7 minutes. Scrape a fork through the couscous to fluff it. Add the mint and almonds and stir them into the couscous with the fork. As you stir, sprinkle on the lemon juice to taste. Serve immediately.