Awesome to know that it belongs in this fascinating genus !

Before researching Dictyna, I looked into Cicurina, which only has two species with (potential) records from Southern California:
* C. utahana, which is much larger and its description doesn't match well either; and
* C. peckhami, which got confused with another species in literature. There are apparent records from Alaska, Canada, and "California."
The type female (from "America sept. Pacifica") measures 3 mm, which is close enough in size.

Hence it should be C. peckhami, unless one of the uncommon, and localized, Northern Californian species has a surprisingly large range extension, or this is an undescribed species ...

For completeness, here is the original 1898 description of C. peckhami, as "Cryphoeca Peckhami", by Simon (in Latin):
"Cephalothorax obscure fulvo-rufescens, laevis et nitidus, sat convexus, ovatus, antice parum attenuatus. Oculi antici inter se contigui, in lineam leviter procurvam, medii lateralibus multo minores. Oculi postici in lineam procurvam, magni et inter se subaequales, medii (plani et vitrei) inter se quam a lateralibus saltem duplo remotiores. Abdomen ovatum, fulvo-testaceum, fulvo-pubescens, postice arcubus transversis fuscis notatum. Partes oris infuscatae. Sternum pedesque fulvo-rufescentia, tibiis 1' paris aculeis 2-2, tibiis 2' paris aculeo unico, metatarsis quatuor anticis aculeis 2-2, subtus armatis. Area genitalis fusco-rufula, pilosa, foveola parva media impressa."

with well over 100 species in NA and is undergoing a revision so there may be others. All I can do at this point without genitalia is a best guess at genus ... even then there are currently only a handful of diagrams freely available online to compare to that I'm aware of and they can be very difficult to ID.

It is not unlikely that it is an undescribed species, as most of the other Californian species appear to have a very small endemic range;
unless someone concludes that the Latin description of C. peckhami matches the specimen nicely ...