Make the whipped feta and white bean dip: Add the cannellini beans, feta, basil, lemon juice, olive oil, salt, and pepper to a food processor. Blend until smooth and creamy, adding cold water 1 tablespoon at a time as needed to reach your desired consistency.
Season the tomatoes: Add the sliced heirloom tomatoes to a bowl or plate and drizzle with olive oil and red wine vinegar. Sprinkle with smoked paprika and flaky sea salt, then gently toss and let sit for 5–10 minutes.
Toast the sourdough: Lightly brush the sourdough slices with olive oil and toast in a skillet over medium heat for 2–3 minutes per side, until golden and crisp. Cut into smaller pieces for dipping if desired.
Assemble the dip: Spoon the whipped feta and white bean mixture onto a shallow serving plate and spread it out using the back of a spoon.
Finish and serve: Layer the seasoned heirloom tomatoes over the dip, spooning some of their juices over the top. Finish with fresh basil, cracked black pepper, flaky sea salt, and a drizzle of olive oil. Serve with the toasted sourdough.