Coconut Chickpea Curry

1 Tbsp oil
1 large red onion
5-6 cloves garlic
1 inch nub grated ginger
2 tsp curry powder
1 tsp turmeric
1 tsp cumin
Salt to taste
30oz crushed tomatoes
30 oz chickpeas
15 oz coconut milk
1/2 tsp fish sauce
Re-season to taste
Finish with lime and cilantro