Preheat oven to 425 degrees F.
Spread the pitted cherries in an even layer on a baking sheet lined with parchment paper. Roast for about 20 minutes, stirring every 10 minutes, until the cherries start to look wrinkled and the juices start to thicken.
While the cherries roast cook the couscous. Pour the water into a medium saucepan and bring it to a boil over high heat. Remove the pan from heat and pour in the couscous and salt. Stir to evenly moisten the couscous.Cover the pan and let it sit for 10 minutes. If the couscous hasn't absorbed the water or still tastes crunchy after this time, cover and let it sit for a few more minutes.Gently break apart and fluff the cooked couscous with a fork.
In a small bowl whisk together the olive oil, garlic, honey, chipotle in adobo, chili powder, oregano, salt and pepper.
Pour the olive oil mixture into the couscous and toss well, Stir in the arugula or spinach and the walnuts. When the cherries are ready gently scrap the cherries and any juices left on the pan into the couscous. Gently toss to combine.
Cut a slit down the length of each poblano. Use your fingers (you might want to wear gloves) and a paring knife to remove, and then discard, the membranes and seeds from each pepper.
Stuff the peppers with equal amounts of the couscous and then stuff the brie inside the peppers, right on top of the couscous. Brush the outside of the pepper with olive oil and bake for around 25 minutes, until the tops are roasted and golden and the pepper is tender all around. Serve peppers immediately, with the slit side up and garnished with arugula and any extra cherries. Eat!