Make the couscous according to the directions. Uncover and fluff with a fork. Transfer the couscous to a large bowl and let cool.
To the couscous, add the artichoke quarters, cherry tomatoes, scallion, chickpeas, cucumber and mint.
Remove the breasts from the roast chicken - reserve the rest of the chicken for another use. Remove skin and cut the breasts into small pieces. Add the chicken to the couscous.
In a small bowl, whisk together the reserved lemon juice, olive oil and the reserved artichoke liquid. Season with salt, pepper, and a little cayenne pepper, to taste. Pour this dressing over the couscous mixture and toss lightly to combine.