One of the most popular recipes that I ever put on my blog was my Basil Vinaigrette. People went nuts for how it added the perfect pop of acidity to just about anything. This is the same basic recipe but calls for cilantro instead of basil, which has the same all-purpose versatility but with more of a Tex-Mex vibe.
In a high-powered blender, combine the shallot, cilantro, garlic, red pepper flakes, oil, vinegar, and salt. Blend for 1 to 2 minutes, until very smooth.
Adjust the salt as needed and season with pepper.
Notes
The dressing will keep in an airtight container in the fridge for up to 3 days.