1Cut tomatoes into thick (at least 1/4 inch) slices. Place tomatoes in colander; sprinkle with salt. Let stand about 30 minutes to pull out water. Pat tomatoes dry with paper towels.
2Pour buttermilk into shallow bowl. In separate shallow bowl, place flour; season with salt and pepper. Dip tomatoes into buttermilk, coating both sides; gently shake off excess. Dip tomatoes into flour, coating both sides; gently shake off excess.
3In deep fryer or heavy saucepan, heat oil over medium-high heat (375°F). Fry 2 tomatoes at a time in hot oil 3 to 5 minutes, turning once, until golden brown. Drain on paper towels. Serve warm.