Line a 9×11-inch pan with parchment paper.
In a medium bowl, mix together the tahini, honey, and vanilla until well combined. Stir in the oats, cranberries, chia seeds, pumpkin seeds, sunflower seeds, and salt.
Spread the oat mixture evenly in the prepared pan, pressing it down very firmly with your bands or the base of a cup.
Place the chocolate and coconut oil in a microwave-safe bowl or measuring cup and microwave on high in 20-second increments, stirring in between, until the mixture is completely melted and smooth. Pour the chocolate mixture over the oat mixture, using a spatula or the back of a spoon to spread it out evenly over top.
Cover and freeze until set, 30 minutes, or refrigerate until set, 1 to 2 hours.
Remove from the pan. Cut in half lengthwise and then into eight strips, making sixteen bars.
