Combine the salt and water in a pitcher and stir until the salt has dissolved.
Rinse the cucumbers thoroughly and snip off the blossom end stem. Set aside.
Place the peppercorns, pepper flakes, garlic, dill seed, and fresh dill into a 1-gallon crock. Add the cucumbers to the crock on top of the aromatics. Pour the brine mixture over the cucumbers to completely cover. Pour the remaining water into a 1-gallon zip-top plastic bag and seal. Place the bag on top of the pickles, ensuring that they are completely submerged in the brine. Set in a cool, dry place for 3 days.
Check the crock after 3 days. Fermentation has begun if you see bubbles rising to the top of the crock. After this, check the crock daily and skim off any scum that forms. If scum forms on the plastic bag, rinse it off, and return to the top of the crock.
The fermentation is complete when the pickles taste sour and the bubbles have stopped rising, 6 to 7 days. Once this happens, cover the crock loosely and place in the refrigerator for 3 days, skimming daily or as needed. Store for up to 2 months in the refrigerator, skimming as needed. If the pickles become soft or begin to take on an off odor, discard them.