Heat the olive oil in a medium saucepan over medium heat; add the garlic and shallots and cook, stirring frequently, until fragrant, about 2 minutes. Add 2/3 cup water, the bell peppers, oregano, 1 teaspoon salt and pepper to taste, bring to a boil over high heat and cook until the peppers just begin to soften, 2 to 3 minutes. Stir in the couscous, immediately cover and remove from the heat. Let stand, covered, until the liquid is absorbed and the couscous is tender, about 7 minutes.
Transfer to a platter or large bowl and serve with lemon wedges for squeezing.