While large seeds such as beans might split, cucumber seeds generally sprout fine without soaking. However, if you want quick germination, soak the seeds before planting. After soaking, plant the seeds in a full sun area in well-draining soil.
Soaking cucumber seeds before planting accelerates seed germination. Warm temperatures combined with water directly activate the seed's growth hormones, giving you a head start. The plants that emerge won't be better; they'll just be faster.
There are two main methods to soak seeds. Moisten a paper towel, then lay your seeds on the towel and cover them with a second moist towel. Leave the seeds overnight, and then plant them. Alternatively, soak the seeds for up to eight hours in a glass jar fitted with a screen lid, then drain the jar, rinse the seed, add lukewarm water and lay the jar on its side. Repeat the rinsing and draining two more times that day, and repeat it for the next two to three days until you see small roots, then remove the seeds from the jar and plant them. Either method works.
Keep the soaking seeds in a warm room so they can sprout properly. If you notice seeds that have split, discard them; plant all intact seeds after the soaking.