In a 6- to 8-quart pan over high heat, bring 4 to 6 quarts water to a boil. Rinse kale; cut out and discard stems and tough centers of leaves. Add kale to boiling water and cook, stirring occasionally, until bright green and tender to bite, about 5 minutes. With a slotted spoon, transfer kale to a colander to drain. Add pasta to water and cook, stirring occasionally, until barely tender to bite, about 10 minutes. Drain pasta, reserving 1 cup cooking liquid; return pasta to pan.
Meanwhile, arrange bread slices in a single layer on a 12- by 15-inch baking sheet. Bake in a 350° regular or convection oven, turning once, until crisp and dry, about 15 minutes total. Rub one side of each bread slice with garlic clove; discard any remaining clove. Let bread cool, then seal in a heavy plastic bag and crush with a rolling pin or whirl in a food processor into coarse crumbs.
Coarsely chop kale. In a 10- to 12-inch frying pan over high heat, stir 1 tablespoon pressed or minced garlic and chili flakes in oil just until garlic is fragrant (but not brown), 1 to 2 minutes. Add lemon juice and kale and stir until liquid is evaporated, 2 to 3 minutes. Add salt and pepper to taste.
Stir kale mixture, ricotta cheese, 1/2 teaspoon salt, and reserved 1 cup pasta-cooking liquid into pasta. Divide equally among four bowls and sprinkle with bread crumbs and parmesan cheese.