Make the white bean dip: Add the cannellini beans, garlic, lemon juice, lemon zest, olive oil, water, salt, and pepper to a food processor.
Blend until smooth and creamy, scraping down the sides as needed. Add an additional tablespoon of water if you'd like a looser consistency. Taste and adjust seasoning with more salt or lemon juice as desired.
Make the olive mix: Dice the shallot, slice the olives, chop the parsley. Combine all the olive mix ingredients to a bowl and add the lemon juice, olive oil, salt and pepper. Mix and season to taste.
Season the tuna: Pat the tuna dry and season all sides with the salt. Press the cracked black pepper evenly over the exterior.
Sear the tuna: Heat the neutral oil in a skillet over high heat until shimmering. Sear the tuna for about 30–45 seconds per side, including the edges, until a thin crust forms while the center remains rare. Transfer to a cutting board and let rest for 2 minutes before slicing thinly. Make sure to not wait longer than 2 minutes as the tuna will continue to cook.
Assemble: Spread white bean dip in an even layer into your shallow serving bowl. Top with olive mix, followed by slices of seared tuna. Drizzle some of the olive mix juices over top the plate. Serve with crispy bread.