Pre-heat oven to 425° and line a baking sheet with foil.
Heat oil in a large skillet over medium high heat. Add rapini and swiss chard and begin to sauté. After about two to three minutes toss with chili flakes, lemon juice and zest, salt and pepper.
Sauté for an additional five to six minutes or until rapini has wilted a fair bit. Set aside.
To make the sandwich, spread one cup of pesto on each of the cut sides of the focaccia. Top bottom half with the sautéed veggies and grated cheese. Close the sandwich and place it on the prepared baking sheet and into the oven for five to six minutes or until cheese is melted and gooey. Remove from the oven and let sit for five minutes before cutting it into four sandwiches.
Enjoy!
Collard greens pesto:
Bring a large pot of salted water to a boil. Add collard greens and blanch for about a minute.
Pour the greens into a colander and run under cold water for about two to three minutes to cool the greens. Squeeze out as much water as possible and roughly chop the greens.
To make the pesto, add everything to a food processor and pulse until smooth and creamy.