Make Sichuan pepper salt: Toast a couple tablespoons green Sichuan peppercorns in an oven or dry skillet until fragrant but not browned. Let cool, then grind to a coarse powder in a spice or coffee grinder. Sift out any large husks that don't break down. Combine 2 teaspoons Sichuan pepper powder with 4 teaspoons fine kosher or sea salt and mix well.
Prep seafood: Use kitchen shears to cut through the bottom shell of the lobster tails, splitting them open top to bottom but leaving intact. Cut each tail into large chunks. (If using a whole lobster, cut into large pieces or have fish monger do for you, cracking each shell so that sauce can seep in when cooking and so it's not necessary to crack at table.) Use shears to cut shrimp shells along back and remove vein, but leave shell on. Leave scallops whole. Dry all seafood pieces well, then dredge them in a bowl of corn starch to lightly but thoroughly coat each piece.
Heat oil in a wok or deep saucepan to 375°. Use enough oil to cover or nearly cover the pieces. Working in batches, add shellfish pieces to hot oil and deep fry, moving gently so they don't stick together. The oil will bubble furiously and splatter, so be careful (a deep sauce pan helps with this). Make sure to retain heat at 375°, or a furious bubble, and cook pieces for about 2 to 2½ minutes, until they are crisp and just starting to turn gold. Remove to paper towels.
Discard frying oil, clean wok, and return to high heat. When hot, add 4 tablespoons oil. Lower heat to medium and add garlic slices. Stir-fry until they are soft, then add ginger and Sichuan ground chilies and cook briefly. Add the whole Sichuan chilies and Sichuan peppercorns and stir-fry briefly. Do not brown. Add back the shellfish and mix thoroughly in the sauce. Drizzle sesame oil around the outside of wok and stir again. Sprinkle lightly with Sichuan pepper salt, stir final time and plate. Garnish with cilantro, and serve with green Sichuan pepper salt as a dip.
