Peel mangos and remove pit and discard. Chop flesh coarsely and purée in a food processor. Set aside.
Place coarsely chopped sweet onion, garlic cloves and seeded habaneros in a food processor and purée.
Place coriander seed in a heavy pan and begin to heat on medium to toast seed, stirring to prevent burning. Remove seed from heat when aromatic and grind in a spice mill or a small coffee grinder. Alternatively, you may certainly use prepared ground coriander.
Place vegetable purée in a heavy non-reactive pot and add sea salt and ground coriander and sauté on medium for 10 minutes or until aromatics are fragrant, stirring frequently.
Add apple cider vinegar and coconut sugar and continue to simmer for 10 minutes.
Remove from heat and add lime juice and mango purée, stirring well to combine.
Optional: press sauce through a sieve to remove any pulp to produce the smoothest sauce texture. The texture is perfectly fine without this step.
Place in bottles or jars and store in refrigerator.