In general, Fusion Summoning does not target the Fusion Materials. The selection of Fusion Materials and the Fusion Summon itself happen during the resolution of an effect, which is beyond the point where targeting can happen.
However, there is one effect I found that targets a card and performs a Fusion Summon based on the target, but it cannot be directly applied to this scenario:
The Eye of Timaeus (Normal Spell Card)
(This card is also always treated as "Legendary Dragon Timaeus".)
Target 1 "Dark Magician" monster you control; Fusion Summon 1 Fusion Monster from your Extra Deck that lists that monster on the field as a Fusion Material, using it as the Fusion Material. You can only activate 1 "The Eye of Timaeus" per turn.
In this case, it is not the Fusion Summon that targets, but the Spell Card itself that does. If you were to find a way to change the name of Maiden with Eyes of Blue to a "Dark Magician" card (Dark Magician Girl, etc.) with a card effect**, then the use of The Eye of Timaeus to perform a Fusion Summon with it, that would cause Maiden with Eyes of Blue to chain with it and apply her effect.
However, after reviewing every other card that is able to perform a Fusion Summon, none of them use the "Targeting" language that The Eye of Timaeus uses with respect to their Fusion Summoning effect. As a result, none of them would trigger Maiden with Eyes of Blue's effect.
**I do not see any cards with an effect that would accomplish this, and it seems likely that whatever effect would accomplish this would probably Target Maiden with Eyes of Blue anyways and set off the effect that way.