1/2 cup crumbled feta (Maria suggest sheep's milk)
Bring the water to a boil in a small saucepan. Remove from heat and add the couscous, salt, and saffron (if using). Cover, set aside, and let sit until the water has absorbed, about 10 minutes. Fluff the couscous with a fork and transfer to a serving dish, spreading and fluffing again. Let cool.
Combine the lime zest, juice, olive oil, honey, the remaining 1/4 teaspoon salt, and pepper in a jar with a tight lid. Shake until the dressing has combined.
Once the couscous has combined, add the watermelon, celery, and mint. Drizzle the mixture with the dressing and gently toss. Let sit for 30 minutes (if you have time) then top with extra mint, feta and an extra drizzle of olive oil. Taste and add salt and pepper to your liking and serve.