For the buttermilk dip, heat the olive oil and the frying peppers in a small skillet over medium-low heat, seasoning them with ¼ teaspoon salt. Cook the peppers slowly, turning them often, until they are tender at the stem, about 15 minutes.
Pinch out the pepper stems and most of the seeds, and put the peppers in a blender. Add the olive oil from the skillet and the garlic, buttermilk, sour cream, sugar, basil, lemon juice, and ½ teaspoon salt. Process until smooth. Pour into a bowl for serving. (This sauce can be made a few hours ahead and kept refrigerated.).
For the fritters, heat the 4 cups oil to 370°F While the oil is heating, shuck the corn, cut the kernels shallowly off the cobs, and then scrape the rest of the pulp with the back of the knife. Measure out 2 cups of kernels and pulp.
In a medium bowl, sift together the flour, baking powder, and 1 teaspoon salt. In a large bowl, whisk together the egg whites, beer, remaining tablespoon of canola oil, tarragon, lemon zest, and reserved corn. Add the flour mixture and whisk quickly to combine. (Don’t overmix—a few lumps are okay.).
Working in batches, drop the fritter mixture by the teaspoonful into the hot oil. Cook until dark golden brown, about 3 minutes. Drain well on paper towels and serve with the buttermilk dip.