Wash the cucumbers thoroughly under cold water, then slice them uniformly and set aside.

In a saucepan, combine vinegar, water, kosher salt, and sugar. Bring to a boil and dissolve the salt and sugar.

Sprinkle in the red pepper flakes and mustard seeds into the warm brine and let steep.

Pack the cucumbers tightly into sterilized jars, adding garlic cloves and spicy peppers for flavor.

Ladle the hot brine over the cucumbers, ensuring they are fully submerged with headspace.

Seal jars securely and let cool for 30 minutes before refrigerating or processing for long-term storage.