1) Heat a small skillet over medium heat. Add the cumin and cook, stirring until toasted and fragrant, about 1 minute; transfer to a large bowl.
2) Add the oil, lime juice, 1/2 tsp salt and 1/4 tsp pepper to the bowl and whisk to combine.
3) Add the chickpeas, celery, tomato and onion and toss to combine. Let sit, tossing occasionally, for 15 minutes.
4) Fold in the feta before serving.