Soak the sliced radicchio in an ice water bath for at least 15 minutes. This will help to tame any bitterness in the radicchio. Drain well.
Make the dressing by whisking together the lemon juice, Dijon mustard, Greek yogurt, garlic and chives in a small bowl. Whisk in the buttermilk, Tabasco Garlic Pepper Sauce, Tabasco Red Pepper Sauce and salt. Adjust seasoning to taste, adding more Tabasco Red Pepper sauce if you want your dressing more spicy.
Go through the crab meat and make sure it is free of shells. Divide the crab meat into 4 bowls (about 1 cup each). Add the radicchio, radishes, roasted corn kernels, avocados, Fresno chills and chives to each bowl. Dress with the Buttermilk Garlic Pepper Dressing and serve immediately.
If you can't find Tabasco Garlic Pepper Sauce, simply substitute Tabasco Original Red Pepper Sauce.Dressing adapted from Southern Buttermilk Salad Dressing, New York Times.