Bring a large pot of salted water to a gentle boil. Set out a baking tray lined with a clean tea towel or paper towels. Remove stems from collards by placing them one at a time on a cutting board. With a sharp knife, start at the thinnest tip of the stem (near the top of the leaf) and cut straight down, as close to the stem as you can cut. Repeat on the other side. Reserve stems for making stock, compost, or use for dog treats. When water comes to a boil, place a few leaves at a time into the water. Cook for about 60 to 90 seconds, until the leaves are bright green and tender. Use tongs to remove collards and place on lined baking tray. Layer towels in between leaves so they dry.
To make the filling, place garlic, jalapeño and ginger in a food processor. Pulse until finely chopped. Add walnuts, shiitake, hemp seeds and scallions. Pulse again till everything is roughly chopped. Add toasted sesame oil, soy sauce, and lime juice. Pulse again till combined.
To make the tahini sauce, whisk ingredients together in a small bowl. Add more or less water to thin to desired consistency.
To make the wraps, lay a collard leaf on a cutting board. Overlap the sides to close the gap where the stem was cut out. Spread about a tablespoon of tahini sauce on the leaf. Place 1 to 2 tablespoons or so of filling on the end closest to you. Tuck the sides in first, then begin to roll away from you. Place finished roll seam-side down and cut in half. Arrange rolls on a plate and serve drizzled with more tahini sauce.
