In a medium bowl, combine shrimp, calamari, garlic, chile flakes, parsley, ½ cup oil, 2 tbsp. lemon juice, and ½ tsp. salt. Chill, stirring often, 1 to 5 hours.
Pour the shrimp, calamari, and marinade into a colander over a bowl. Brush marinade over cut sides of bread; grill on each side over high heat (450° to 550°) until grill marks appear, 3 to 5 minutes. Cut into slices.
Grill the shrimp and calamari tubes, turning once, just until firm, 3 minutes. Meanwhile, using tongs, drop tentacles in clumps onto grill just to firm up, then spread out to cook evenly, 4 minutes total. Slice up the calamari, and put it and the shrimp in a dish and drizzle with remaining oil, lemon juice, and salt.
Add to a platter. Serve up with some aioli, more of the marinade mixture for dipping, and place lemon wedges around the seafood. A squeeze of lemon and garnish with fresh parsley and cilantro. Serve with the crusty bread.