Spicy Black Bean and Corn Tacos

hazelnuts, coarsely chopped

raw pumpkin seeds

ears of corn, shucked

medium jalapeño, seeded, finely chopped

crushed red pepper flakes

chopped cilantro, plus more for serving

olive oil, divided

fresh lime juice, divided, plus lime wedges for serving

kosher salt, divided

red onion, coarsely chopped

black beans, rinsed, drained

ground cumin

small corn tortillas

sour cream

large avocado, thinly sliced