Combine the cilantro, parsley, oregano, mint, and garlic in a food processor. Pulse until the herbs are finely chopped. Add the salt, red pepper flakes, olive oil, and red wine vinegar. Pulse for a few more seconds until combined. Taste, and adjust seasonings as needed.
If you don't have a food processor, you can still make this recipe. Use a sharp knife to finely chop the herbs and garlic, and mix in the rest of the ingredients by hand.
While I don't usually have this issue, sometimes pulsing or blending the olive oil with the other ingredients can lead to a bitter taste. To prevent this, mix in the olive oil by hand after you chop the herbs.
Leftovers will last in an airtight container in the fridge for 2 to 3 weeks. Stir well before using.