In a medium skillet, heat 1/4 cup of the olive oil until shimmering. Add the garlic, sage and rosemary and cook over moderately high heat, stirring, until fragrant and the garlic is just beginning to brown, about 1 minute. Add the beans and toss to coat.
Transfer the cannellini beans to a food processor. Add the water, season with salt and cayenne and process to a fairly smooth puree. Transfer the dip to a small serving bowl, drizzle the remaining 2 tablespoons of olive oil on top and serve with pita chips.