Note: It is HIGHLY recommended to use gloves while handling habanero peppers. The oils from these peppers can stay on your skin even after washing, and you risk getting it in your eyes.
Begin by giving half of a white onion a rough chop, juice the limes, and roughly chop the orange bell pepper (without the seeds).
Peel and remove the seed from the mango. Use a food processor or blender to puree mango completely.
Put gloves on. Use a sharp knife to remove the stem from the habanero peppers. Remove the seeds for a milder sauce.
Try to keep the peppers mostly whole and intact, so that you know how many you are adding to the sauce.
To a food processor or blender, add all of the ingredients except for the habaneros.
Blend until smooth.
Start by adding just one or two habaneros (with or without seeds). Blend, then taste.
Add the remaining habaneros if you want more heat. Blend until smooth.
Taste and adjust levels of spice, sugar, or salt accordingly.
(Optional) You can run this sauce through a mesh strainer if you want a smoother sauce, but I found this to be mostly unnecessary.
Serve on tacos, with rice bowls, or on a salad!