DRESSING: Blend first 9 ingredients with 1 tablespoon water in a food processor until smooth. With motor running, slowly drizzle in oil until emulsified. Stir in Parmigiano Reggiano and chill for at least 2 hours.
FRICO: Heat oven to 350°F. Pulse focaccia pieces in food processor until fine crumbs form. Add Pecorino Romano, salt, black pepper, and red pepper flakes and pulse 2 to 3 times, until well combined. With motor running, slowly drizzle in oil.
Line a rimmed baking sheet with parchment paper and oil the paper. Spread out mixture on prepared baking sheet until it’s ⅓ inch thick. Cover with another piece of oiled parchment paper and top with another baking sheet to flatten. Bake until just starting to brown, 10 to 15 minutes. Remove top baking sheet and parchment paper and bake for 10 to 15 minutes more, until golden brown.
Cool completely, then break into bite-size pieces.
SALAD: Cook pancetta in a medium sauté pan over medium heat until crispy, 7 to 10 minutes.
Combine romaine lettuce, radicchio, arugula, kale, radishes, and fennel in a large bowl. Stir in enough dressing to fully coat salad (there may be some left over). Toss well.
Top with pancetta, frico, black pepper, and grated cheese. Serve immediately.