In a medium saucepan, bring the broth or water, paprika, saffron (if using), harissa or hot sauce, 1/2 tsp. salt, and a pinch of white pepper to a boil over medium heat. Cover and reduce the heat to low to keep the broth at a simmer. Taste and adjust the seasonings. Meanwhile, heat 1/4 cup of the olive oil in a large sauté pan over medium heat. When the oil is hot, add the onion and red pepper and cook until the vegetables are soft but not browned, 8 to 10 min. Add the couscous and stir to coat the grains with oil. Remove the pan from heat. Add the simmering liquid to the couscous and stir to evenly distribute the liquid. Cover the pan and let it sit until all the liquid is absorbed and the couscous is tender, 5 to 7 min. Remove the lid and fluff the couscous with a fork. Set aside to cool for 15 min.
Whisk the remaining 3 Tbs. olive oil with the orange zest, orange juice, and 1/2 tsp. salt. Toss with the couscous. Let cool completely and then transfer to an airtight container or a bowl covered with plastic wrap and refrigerate. Put the scallions, almonds, dried currants, and parsley in a separate container and refrigerate.
Just before heading to the picnic, stir the scallions, almonds, currants, and parsley into the couscous. Taste and adjust the seasonings as needed.