In a small skillet, combine the garlic, olive oil, coriander, and salt. Bring to a simmer over medium heat and cook just until the garlic is fragrant, about 1 1/2 minutes. Remove from the heat and let cool.
Transfer the oil mixture to a blender. Add the cilantro, lemon juice, jalapeño, and 1/4 cup water and blend until smooth. If necessary, season with additional salt to taste. Use immediately or store in an airtight container in the refrigerator for up to 1 week.