Before you begin: Sterilize 4 pint-size canning jars and prepare two-piece canning lids according to the manufacturer’s instructions.
Trim green beans so that they will fit standing up inside the pint jars. The straighter the beans, the nicer it looks in the end. Slice pepper into strips.
In a small pot over high heat, bring water, vinegar, and salt to a boil. Meanwhile, into each pint jar, add ¼ teaspoon cayenne, 1 teaspoon dill seed, and 1 clove garlic.
Pack green beans and pepper strips into jars. You want these to be pretty tightly packed, but with enough room for the liquid you’ll be adding.
Pour the boiling liquid into the pint jars, leaving ½-inch headspace. Remove air bubbles and wipe rims of jars with a dampened clean paper towel; adjust the twopiece metal canning lids.
Process jars in a boiling water canner for five minutes. Let the dilly beans stand at least 3 weeks before opening. Refrigerate after opening.