Masgouf / Iraqi Grilled Fish

Name: Masgouf / Iraqi Grilled Fish
Prep time: 30 min
Cook time: 20 min
Total time: 50 min
Cuisine: Middle Eastern
Ingredients: 1 lb. white fish fillets; 2 tsp. salt (divided); 2 tsp. curry (divided); 1 large onion; 2 cloves garlic; 3 T. vegetable oil; 2 medium tomatoes; 1 1/2 cups chopped parsley; 1/2 6 0z. can tomato paste; 2 T. vinegar; 2 T. lemon juice; 1/2 cup water; 1/2 tsp. cayenne pepper (optional)