Place the tofu cubes in a bowl. Add the apple, plums, raisins, grapes, and pecan pieces. Toss gently using your hands or two wooden spoons. Into a separate bowl, measure the mayonnaise, buttermilk, and chives. Sprinkle lightly with sea salt and pepper. Whisk to combine, then taste for seasonings. Drizzle about two-thirds of the dressing over the tofu salad, saving the remaining dressing for the tomatoes and romaine. Gently toss the tofu salad to coat it thoroughly.
Arrange the romaine leaves on a serving platter. Arrange the slices of tomatoes in a circular pattern over the romaine leaves. Drizzle the remaining dressing evenly over the top. Cut each avocado in half, remove the seed, then, using a spoon, scoop out each half, leaving the peel behind. Arrange the peeled and seeded avocado halves cut side up over the salad. Fill each avocado half with tofu salad. Enjoy it.