Line a 9x13-inch baking pan with parchment paper.

Blend oats, coconut flakes, and salt in a food processor until a powder-like consistency is reached. Add tahini and agave syrup; blend until a fluffy paste is formed. Mix in protein powder until well combined. Blend in milk 1 tablespoon at a time, thinning the paste until it is spreadable.

Spread paste into the prepared pan. Refrigerate until firm, about 30 minutes. Cut into squares and serve chilled.