Stir oats, peanut butter, strawberry preserves, honey, protein powder, flaxseed, and vanilla until a thick, cohesive mixture forms.
Chill the mixture for 30 minutes so it firms enough to shape.
Scoop 18 portions. Flatten each portion, add about 1/2 teaspoon preserves in the center, fold the mixture around it, and roll into a ball.
Melt the chocolate and coconut oil together in short microwave intervals, stirring until smooth.
Dip or drizzle each ball with chocolate and place on parchment. Sprinkle with flaky salt if desired.
Chill for 30 minutes, until the coating is set.