Sear the salmon. Season the salmon with salt and pepper. Heat olive oil in a large skillet over medium heat. Add the salmon and cook 3–4 minutes per side, until lightly charred and cooked through. Transfer to a plate and set aside.
Sauté the aromatics. In the same pan, add more oil if needed and sauté the shallot for 2–3 minutes until softened, then add the garlic and cook for 30 seconds until fragrant.
Toast the couscous. Add the pearl couscous and toast for 2–3 minutes, stirring often, until lightly golden.
Cook the couscous. Pour in the stock and bring to a gentle boil. Reduce heat, cover, and simmer for 10 minutes, or until the couscous is tender and most of the liquid is absorbed.
Add the vegetables. Stir in the peas and corn during the last 2–3 minutes of cooking to warm through.
Make the dressing. Whisk together the lemon juice, olive oil, Dijon, parsley, salt, and pepper.
Finish and serve. Remove the couscous from heat and toss with the lemon herb dressing. Fluff and adjust seasoning as needed. Serve with the seared salmon on top and charred lemon wedges.