Drain and rinse the beans thoroughly under cool running water. Pat them lightly dry if they are especially wet, which helps prevent the dip from becoming thin.

Add the beans, olive oil, lemon juice, garlic, kosher salt, black pepper, and chopped rosemary or parsley to a food processor or high-powered blender.

Process until mostly smooth, scraping down the sides once or twice. Add cold water 1 tablespoon at a time while blending until the dip is soft, silky, and easy to spread.

Taste the dip and adjust with more salt, lemon juice, or olive oil as needed. Add cumin, red-pepper flakes, or lemon zest if desired.

Transfer the dip to a serving bowl and swirl the surface with additional olive oil. Finish with fresh herbs, lemon zest, or red-pepper flakes, then serve with pita, crostini, crackers, or raw vegetables.