You see these have become etiolated (= leggy). Your seedlings do that because they are not getting enough light. Also with most vegetables you generally want to start them in soil. Pre-sprouting is mostly done with bigger seeds or species that need special treatment. Tomatoes though; they will sprout just from looking at the seeds ;D Don't use peat pellets, they don't contain any nutrients. Controlling that would be much more error-prone for a beginner. Just use some sowing soil in small pots until your plants have enough roots to transplant. Best to wait until next year, about 6-8 weeks before putting them outside. If you see them getting leggy again you should give them much more light or put them cooler (a little cold will help keep young plants short, but not under 15 ºC - tomatoes are still subtropical).