Place a pot of water to boil.
Meanwhile, heat a drizzle of olive oil in a heavy saucepan. Add garlic slices and cook until fragrant. Add the crushed tomatoes and let simmer gently for 10-15 minutes, just enough to lightly cook the tomato and meld the flavors—or, if you like, you can keep it at the barest simmer until the pasta is done. Season sauce with sea salt, to taste.
When the water comes to a boil, salt it generously. Then add your pasta and cook it al dente.
Drain pasta, reserving some of the water. Add trumpets to the pot with the tomato sauce over very gentle heat. Add the young chard and mix until chard is wilted. If the mixture seems too thick, add a bit of the pasta water. Taste and adjust for seasoning.