I agree they're most likely flea beetles - close examination of the pics shows very small holes appearing in leaves. You can try this to control them: 2 parts rubbing alcohol, 5 parts water and 1 tablespoon of liquid soap, mixed in a sprayer, spray all leaves, including the backs, till run off. This 'recipe' is from the Old Farmers Almanac - the only thing that troubles me about it is, it doesn't specify what kind of liquid soap, but I'm guessing an eco dishwashing liquid might be fine, or horticultural soap solution.
Flea beetles will be present in the ground over winter - dig over the soil in autumn/fall to unearth them a bit, then again in spring. Try to delay planting your crops for a couple of weeks after the time you'd normally put them out - this will deprive the beetles of a food source for longer, and delay their laying of eggs, which they do at the base of food plants. Remove your existing crops as soon as they're over, don't leave them in the soil over winter - flea beetle larvae feed at the roots. This is a good time to dig over the area too.
Flea beetles aren't much of a threat in terms of devouring leaves on mature plants, but they can spread bacterial diseases from plant to plant, and are much more of a threat to young plants or seedlings. Treat any crops as soon as you notice anything next year.