Wash and chop peppers and onions. Wear gloves is suggested. Remove most of pepper seeds.
In the bottom of a clean quart jar, add a small handful (1/4 cup loose) of fresh cilantro and 2-3 crushed cloves of garlic.
Next add the diced onion, and some peppers on top. Lightly press to compact and reduce air space as you go.
When the jar is halfway to 2/3 full, add the remaining 1/4 cup of cilantro and then continue filling the jar with peppers, until completely packed full (within top inch of the jar).
On the stovetop, combine 2 cups filtered water with 1 tbsp sea salt. Lightly heat until salt dissolves, but avoid over heating.
Allow brine to cool to room temperature or lukewarm, and then pour over the peppers in the jar until the jar is full and they are fully submerged. Tap and wiggle jar to remove air pockets.
Cover with fermentation weight and airlock lid, to keep veggies submerged below the brine during fermentation.
Set jar in a temperate location (70-75°F) to ferment for 7-14 days.
After 7-14 days, open jar and pour contents through a strainer that is positioned over a bowl to catch the liquid. KEEP the strained brine liquid.
Add all solid contents (peppers, onions, garlic, and cilantro) to a blender. Add 1 tablespoon of fresh squeezed lime juice, and 1/4 cup of the reserved brine liquid. Blend.
Assess the consistency of the fermented hot sauce. Continue to add reserved brine little by little, blending as you go, until the desired consistency of sauce is reached.
Store finished fermented hot sauce in an air-tight bottle or jar in the refrigerator. Shake before use. It should stay good for up to one year in the refrigerator.