In a small saucepan, bring broth, salt and olive oil to a boil over medium-high heat. Once the mixture comes to a boil, stir in the couscous, cover with a tight-fitting lid and remove from heat. Let the mixture stand undisturbed for 5 minutes. Remove lid and fluff the couscous with a fork. Transfer to medium-sized serving bowl and set aside.
Heat a large skillet over medium-high heat and add the olive oil. When the oil is hot, add diced onion and cook 3–4 minutes until translucent. Add the garlic and cook for 1 additional minute.
Add mushrooms to the skillet and toss to coat in the oil. Cook for 23 minutes, then add the chicken broth and kosher salt and cook until all of the liquid has evaporated.
Once the liquid has evaporated, add the mushroom mixture to the bowl containing the couscous then stir to combine and set aside.
In a small mixing bowl, add lemon juice, olive oil, green onion, arugula, cherry tomatoes and salt and pepper. Toss to combine then stir into couscous and mushroom mixture. Serve warm and enjoy!
Serve this couscous alongside a flaky white fish for a light and healthy dinner.