Place tomatoes, onion, lemon juice, cilantro, garlic, coriander, cumin, salt, pepper, and cinnamon in a food processor. Pulse until chopped fine but not pureed. Pour 1/2 the mixture on top of 1/2 of the trout; fold the other side of trout on top. Spoon the remaining 1/2 of the mixture on and around the sealed trout. Add water to the pan; arrange potatoes around the trout. Cover pan with aluminum foil.