Combine chia seeds and water in a glass and set aside for at least 15 minutes.
Preheat the oven to 350 F. Line a muffin pan with liners.
In a large mixing bowl, stir together the flours, baking powder, baking soda and salt until combined.
In another bowl, add the chia seed gel, olive oil, maple syrup, orange juice and vanilla extract. Whisk until smooth by hand. Add to the flour mixture and blend just until moistened but lumpy. Stir in the rhubarb and apricots.
Spoon the batter into 12 muffin cups, filling each cup about 2/3 full. Sprinkle the topping of your choice onto each muffin and bake until springy to the touch, about 25 to 30 minutes. Let cool for 5 minutes, then transfer the muffins to a wire rack to cool completely.