Heat 3 tablespoons of olive oil in a medium pot over medium heat. Add the couscous and toast it for 4-5 minutes, stirring frequently, until it becomes fragrant and turns a light golden color—this step builds nutty flavor into the base. Pour in the vegetable broth and bring to a boil, then immediately reduce heat to low and simmer for 8-10 minutes until all the liquid is absorbed and the couscous is tender. Transfer the couscous to a large bowl and fluff it with a fork, then spread it out slightly to cool for a few minutes while you prepare the other components.
While the couscous cooks, mince the 2 garlic cloves very finely. In a small bowl, whisk together the red wine vinegar, lemon juice, minced garlic, oregano, mustard, salt, and black pepper. Slowly whisk in the 0.6 cup of olive oil until the dressing is emulsified and well combined—this creates a balanced vinaigrette with proper texture. In a separate small skillet, toast the pine nuts over medium heat for 3-4 minutes, stirring constantly, until they're golden brown and fragrant, then set aside to cool slightly. I find toasting the nuts separately ensures they stay crispy and don't get soggy when mixed into the salad.
While the couscous cools slightly, dice the cucumber into 1/2-inch pieces and cut the grape tomatoes in half. Slice the roasted red pepper into 1/4-inch strips. Finely dice the red onion into 1/4-inch pieces—the smaller pieces help distribute its flavor throughout the salad. Chop the fresh parsley, then crumble the feta cheese by hand into small chunks; I prefer President brand as it crumbles beautifully and has great texture. Have the kalamata olives and pepperoncini ready to add.
Add the prepared cucumber, tomatoes, roasted red pepper, kalamata olives, pepperoncini, and diced red onion to the cooled couscous in the large bowl. Add half of the crumbled feta cheese and half of the toasted pine nuts, then add the chopped parsley. Toss everything together gently but thoroughly to distribute all the ingredients evenly throughout the couscous.
Pour the dressing from Step 2 over the couscous mixture and toss well, ensuring every component is coated evenly with the vinaigrette. This is where all the flavors come together—take your time to make sure the dressing reaches the couscous at the bottom of the bowl. Top the salad with the remaining feta cheese and remaining toasted pine nuts just before serving for maximum texture contrast. Taste and adjust seasoning if needed, then serve immediately or at room temperature.