Coat an 8-inch square baking dish with nonstick spray.

Heat oven to 350°F. Combine oats and almonds on a baking sheet and toast in oven for 10 minutes; transfer to a large bowl. Add coconut to baking sheet and toast until golden, 3 minutes; transfer to bowl with oats and add chia seeds.

Meanwhile, process dates in a food processor until a thick paste-like ball forms. Break ball apart then continue to process until paste forms around sides of bowl. Combine date mixture, peanut butter, honey, salt, and cinnamon in a small saucepan over medium heat. Cook until combined, about 2 minutes. Off heat, stir in vanilla.

Add date mixture to oat mixture and mix until thoroughly combined (set down the spoon and get your hands dirty, this is a sticky mixture). Transfer mixture to prepared dish and press into an even layer.

In a double boiler (glass bowl set over a pot of simmering water), melt chocolate until smooth, drizzle or spread over bars. Chill bars at least 1 hour before cutting.

Store in an air-tight container in the refrigerator for up to 1 week.