We have some of these problems, too. Mostly, it is about treating people with respect, IMO.
It is ironic, because this is probably my biggest parenting challenge (teaching dd to treat others with respect even when upset), yet it is also the biggest reason I evolved into a GD parent! (wanting to model/treat dd with respect).
Some things I believe:
-It is ok for a child to have strong feelings and preferences. (wanting Mommy rather than Daddy to do something)
-It is good to honor that preference when practical, but not necessary when impractical (Mommy honestly busy).
-It is ok for a child to be disappointed/angry when things do not go their way.
-It is not ok to scream at anyone.
-It is not ok to throw toys.
When I look at it that way, this issue is largely about teaching our children to handle anger/disappointment appropriately. Maybe labelling those emotions in the moment would help? Tell her to say "I'm angry!" "I wanted Mommy to do it!" instead of screaming "NO!"? I would definitely say that it is Not Ok to yell at Daddy each and every time it happens.
About throwing the toys....in our house, toy throwing is not allowed. Thrown toys are removed (not permanently, of course). So that could be a natural consequence in that particular situation.
HTH a little. Like I said, we struggle too. But, like so many things, I don't think there is an instant "cure"--a consequence that will teach a small child to quickly learn self-control and respect. Those things come with maturity (sigh).
Edited to add: It might be helpful to offer her a choice before Daddy tries to help her--something like "Mommy is busy right now. Would you prefer Daddy to help you, or wait for Mommy?" If she honestly would rather wait than have Daddy do it, then let her ::
::::. She will be able to do these things for herself soon enough anyway, and will definitely outgrow this rigidness about mommy v. daddy helping.