Bring a large pot of salted water to a boil. Cook soba noodles al dente according to package directions. Reserve ¼ cup water before draining noodles. Rinse noodles under cold water, and drain again.
Meanwhile, add the sesame and coriander seeds to a mortar, and grind into a paste (it’s okay if it’s grainy). Whisk in the paprika, honey, oil and vinegar; season with salt and pepper.
In a deep bowl, add the noodles, shallots, carrots, cucumbers, and sauce; toss to combine, adding water 1 tablespoon at a time if sauce seems too thick.
Arrange on a platter, garnish with some more sesame seeds and serve.