Why fry a teaspoon of dal to start an Indian dish?
In a dry dish - eg lemon rice, or a dish following the thoran pattern - a teaspoon  of urad dal will definitely be noticeable by giving a crunchy element. 

Do not forget that indian recipes tend to use old school spoon sizes for measurement - a random piece of contemporary flatware will not give you a good approximation here.

Washing and soaking the urad dal for an hour or so can be a good idea if you do not know hold old the dal you are getting is (especially if cooking such dishes when not in India) - too crunchy urad dal could turn into a molar menace.