Put the flour, salt and sugar into a mixing bowl and stir in the yeast. Mix the oil with 150ml/5fl oz lukewarm water and add to the flour. Mix well until it forms a soft dough, then turn out on the work surface and knead for 10 minutes (or for 4-5 minutes in a mixer with a dough hook).
Sprinkle the work top with the semolina or polenta, or sesame and poppy seeds and roll out the dough as thinly as possible into a rectangle. Cut the dough into 1cm/½in-wide strips. Roll each one between your hands to a pencil shape and place on two lightly oiled baking trays, spaced a little apart. Cover with cling film and leave in a warm place to prove for about 15-20 minutes, or until risen a little. Sprinkle with a little sea salt.
Preheat the oven to 220C/425F/Gas 7 (200C fan). Bake the bread sticks for 10 minutes, or until golden-brown and crisp. They will be soft at this stage. If you prefer drier grissini style-sticks, bake for a further three minutes. Allow to cool completely, then store in a tin for up to three days.