Slicing nuts requires a sharp heavy knife and a firm surface. Slice nuts before you toast them because toasting makes them dry and brittle.
To chop nuts, hold the knife point to the cutting surface with one hand and chop up and down with the other hand on the knife handle. A quick turn in the food processor will also do the trick.
Grinding nuts is tricky because the oil and nutmeat sepárate if they are too finely ground. For pastry, it is very important that the ground nuts be light and dry, not oily. Use a nut grater or grinder and grind just a few nuts at a time. Or grind the nuts in a food processor, then sift the nuts through a sieve.